The car jerks when driving: causes and ways to eliminate them

In most cases, car jerking when driving is a sign of problems in the engine power supply system, ignition or transmission . Before continuing to operate in such a situation, it is better to find out why the car begins to twitch while driving. Some faults that cause these symptoms may pose a safety hazard or cause more serious damage .

In this article we will tell you what to do if the car jerks while driving, how to find the culprit of the problem and fix the problem.

When does this happen

Almost every car enthusiast who has logged more than tens of thousands of kilometers has encountered such a problem as uneven driving of the car, or, in popular parlance, the car simply jerks in some operating modes.

The car jerking can be as follows:

• the beginning of the movement;
• at low speeds;
• with increasing speed;
• at high speeds;
• in all modes at once.

Moreover, it is worth noting that such a malfunction occurs not only on an old car; a new car is also capable of twitching.

It is impossible to say that the cause of uneven running is only a certain part of the car and that it is unique to a specific brand of car.

Based on reviews from car owners, we can conclude that this problem occurs with absolutely any vehicle - an old VAZ “Seven” or a new “Japanese”.

The appearance of uneven movement of the car not only irritates the driver, but can also cause an accident, because at the right moment the car, instead of accelerating, will begin to twitch.

Let's try to figure out in detail what can cause the car to jerk while moving. But to do this, you first need to understand how everything happens.

Quick diagnostics

So, the car is started, the speed is turned on, the clutch is slowly released, and the engine speed gradually increases.

But instead of smoothly starting from a stop and starting to pick up speed, the car begins to jerk - the speed fluctuates, the speed either increases or drops sharply, despite pressing the accelerator pedal.

This can continue until either the twitching goes away on its own and the car begins to confidently gain momentum, or until the engine stalls.

It happens that the car starts moving quite safely, but as soon as the revolutions increase to 2000-2500, uneven movement begins, accompanied by sharp changes in engine operation, as well as in the speed of movement.

The same situation can be observed when reaching medium modes, that is, the engine reaches a certain speed level, after which twitching begins.

It happens that the car starts to jerk every time you change gears.

It is not necessary that uneven running occurs only under certain conditions.

It also happens that the car jerks spontaneously, without any frequency or conditions. That is, the car can jerk just once, in any mode, and then move normally for quite a long time.

Or the car was working normally, but suddenly began to twitch sharply, and this trouble no longer goes away.

In general, there are a lot of options, but one fact remains - the car has an uneven ride, and it is advisable to eliminate it as quickly as possible before the problem gets worse.

The first thing to do is determine under what conditions the twitching occurs. The easiest way to do this is while moving.

You should drive onto a flat section of the road where there is no traffic and start testing.

At first, just get moving, then gradually increase the speed, remembering the behavior of the car and watching the dashboard.

And this must be done until the engine reaches high speeds.

Afterwards, you will need to run the test again to make sure that the conditions for the appearance of twitching are determined correctly. And only after that you can start looking for the reason.

A summary table of the reasons why the car jerks for different types of motors for quick diagnosis.

* applies only to diesel engines that have a Common Rail injection system.

** applies to vehicles equipped with direct injection engines and 6th generation LPG with liquid gas injection installed on them.

*** for cars with an injection system equipped with an electronic e-gas pedal.

**** for carburetors of cars with an electronic ignition system.

How to find the reason and what to do

Auto scanner Rokodil ScanX Pro

On a car with an injector, you need to find out why the car starts to twitch while driving, by diagnosing and reading errors. If there is a BC that displays their codes, no additional equipment is needed, otherwise an OBD II scanner and software for it are required. You can do without additional gadgets and programs, which are also often paid, if you buy a portable car scanner, for example, Rokodil ScanX Pro. Such a device makes it possible to read errors and decipher them, view readings from various sensors, and record data in real time. Common error codes indicate problems with such nodes:

Diagnosis of why the car jerks: video

• P0100-0104 – Mass air flow sensor;
• P0105-0109 –DBP;
• P0110-0114 – intake air temperature sensor;
• P0115-0119, P0125-0126 – coolant temperature sensor;
• P0120-0126, P0220-0229 – TPS;
• P0200-0215, P0251-0296 – injectors;
• P0218 – gearbox overheating;
• P0230-0233 – fuel pump;
• P0335, P0336-0339 – DPKV;
• P0350-0362 – ignition coils, wiring, or control unit.

Without computer diagnostics, you will have to check why the car started to twitch while driving, by inspecting the components one by one. The general sequence of actions is shown below.

Car jerking at low speeds

This problem often occurs when driving at low speeds at low engine speeds.

Checking the engine power system

Often the reason for the car twitching at low speeds is the power system, or rather, a malfunction in its operation.

When starting to move, the required amount of fuel simply does not enter the cylinders; the car is unable to produce the required power to evenly operate the transmission.

At the same time, transmission resistance leads to uneven running.

When jerking occurs at low speeds, first of all you should check all the elements related to the power system, and it makes no difference what kind of system it is - carburetor, injection or diesel.

It is recommended to immediately check the condition of all pipes. Depressurization of the system almost always leads to air being sucked in, which leads to fuel starvation of the engine.

And only after checking the condition of the pipelines can you proceed to the remaining elements of the system, which will be discussed below.

Ignition system

Also, the cause of jerking at low speeds can be the ignition system, especially for injection cars, where the entire operation of the system is controlled and regulated by an electronic unit.

A malfunction of one of the sensors can easily cause the machine to twitch.

The problem is in the “brains”

As they say, “the fish rots from the head.” This leads to a fairly common scenario for the occurrence of “convulsions” in a car. Incorrect ECU software settings. In this case, the twitching makes itself felt, first of all, when the engine is cold. This is due to the fact that the information from the sensors is read incorrectly, not enough fuel mixture enters the cylinders and dips occur when the speed increases. When the car warms up, the check engine light goes out and the twitching stops. This problem can be solved by updating the firmware and proper calibration. Moreover, if you are not confident in your abilities, it is better to contact a service station with professional computer equipment.

At high speeds

But the jerking of the car at high speeds is more related to the ignition system.

In a normally operating engine, the ignition system automatically adjusts to certain conditions by changing the ignition timing.

That is, when necessary, the ignition becomes either a little early or late.

A malfunction in the automatic ignition will cause twitching.

Do not forget that the cause of uneven movement will be not only a malfunction of the system, but also the failure of one of its elements.

And these are only the reasons that can arise with the engine, without affecting the transmission.

You need to immediately narrow the search for identifying the reasons for the car twitching to two engine systems - fuel and ignition, but you should not discount the transmission.

Is it due to the fuel filter?

So, it has been determined that the car jerks only under certain conditions. The fuel system pipes are all normal, but it is believed that the cause lies in the fuel system.

This means that the filters need to be checked next. Often it is because of them that this malfunction appears.

The task of any filter element in the fuel system is to clean the fuel from impurities, but at the same time, these impurities do not disappear anywhere, they remain in the filter itself.

Over time, it becomes so clogged with impurities and dirt that its throughput drops, and greatly.

As a result, the fuel pump pumps as expected, but the fuel does not have time to pass through the filter elements and the engine begins to “starve”, accompanied by the car jerking. There is only one way out here - .

Carburetor cars

If you take into account a carburetor car, then the number of filters it has is 2-3 pieces, but one of them, the usual mesh on the fuel receiver, can be practically discounted.

This mesh is aimed only at catching large particles, so it is practically incapable of becoming clogged to such an extent that it stops the flow of fuel in the required quantity.

But the second filter, usually located in the pipelines leading to the fuel pump, is worth checking.

This filter is designed to catch smaller particles and is not difficult to clog.

The third filter is not available on all carbureted vehicles and is usually located at the fuel inlet to the carburetor. It is also a regular mesh, but only fine.

This filter itself is small, so it often gets clogged.

Older machines had another filter installed - a coarse filter, also known as a sediment filter.

The design of this filter is such that it is not capable of becoming clogged to such an extent that it will not allow fuel to pass through. But this filter will subsequently cause rapid clogging of the fine filter.

If this filter accumulates a large amount of debris and dirt, then eventually it will not begin to clean the fuel from impurities, but, on the contrary, will begin to add them.

Injection car filters

Most modern injection cars are also equipped with three filters.

• The first of them is a mesh for catching large particles installed in the neck of the tank. This mesh is clearly not the cause of the twitching.
• The second filter is located on the fuel pump installed in the tank. This filter is also often a mesh, only with smaller cells; its task is to prevent large debris from entering the fuel pump. It is also unlikely that it can cause a lack of fuel.

But the third filter, a fine filter, is located behind the fuel pump and is quite capable of becoming clogged to such an extent that the pump cannot push the required amount of fuel through it.

On more modern cars, there may be additional filters, which can also cause the car to twitch.

How to fix overclocking failures

1. Check the ignition wires and coils. When a breakdown occurs, the spark plug wires spark and glow in the dark. The engine shakes and jerks. This happens due to age, poor quality parts or poor contact with the spark plugs. The malfunction may be related to the engine temperature. The interwinding resistance of the coils and the thermal operating conditions change together, which is why a gasoline car jerks during acceleration. If you have a diesel engine, jerks during acceleration are definitely not related to the operation of the coils, they are not there.
2. Inspect the spark plugs. Poor contact with the wires, heavy carbon deposits, too lean or rich fuel mixture disable them. Unscrew and check each spark plug as in our article “Diagnostics of internal combustion engine operation using spark plugs,” where we gave examples of faulty spark plugs.
3. Check the fuel, oil and air filters. Over time, they become clogged, which leads to deterioration in dynamics, increased fuel consumption and periodic failures. You can replace them yourself; they are inexpensive and easy to install.

If the tips above did not help, only diagnostics will solve the reason for this behavior of the gas pedal. Incorrect operation of systems, errors, composition of the fuel mixture - the diagnostician will name a specific malfunction.

Even if the engine is working properly, the car may move jerkily when accelerating. Motors that meet environmental standards Euro-4 and higher have this unpleasant property. The point is the reaction of the electronic throttle to pressing the gas pedal. It is nonlinear for the first 3–4 centimeters of travel. Because of this, failure may occur during overclocking.

Chip tuning to Euro-2 or Euro-0 standards improves the response of the gas pedal and solves the problem. ECU firmware has a number of other advantages:

• Improves overall dynamics, idle performance and traction at low speeds;
• The car does not stall when the air conditioning is on;
• Gear shifts smoother;
• Fuel consumption is reduced while maintaining driving style.

Video from our partner on how chip tuning copes with failures and “brooding” of the accelerator pedal on Gazelle Next:

Contact ADACT partners in your city for chip tuning. We guarantee a 10-day test drive, money back and replacement if you don't like the firmware.

Other elements of the fuel system

Now on to other elements of the fuel system.

Fuel pump.

The next culprit for uneven running may be the fuel pump.

In carburetor cars.

A mechanically driven diaphragm fuel pump is often used here.

So, even a small rupture of the membrane will cause the pump’s performance to drop sharply.

The pump valves may also be to blame. They can easily break the sealing of the device’s chambers, which leads to a drop in fuel supply.

Injection car.

The fuel pump can also cause jerking. On such cars, since the pump is located in the tank, it is electrically driven.

A decrease in device performance leads to the problem described in this article. Here you need to consider a specific case separately.

Now directly about the carburetor.

Because of this, uneven running of the car is also possible. Often such a malfunction occurs due to severe clogging. Debris and dirt can block channels, clog jets, etc.

Sometimes the reason lies in the accelerator pump. A diaphragm accelerator pump is installed on carburetors, the task of which is to increase the fuel supply when the gas pedal is sharply pressed.

But if the membrane is torn, then the accelerator pump will not be able to increase the supply of gasoline, and hence fuel starvation.

Injectors.

For injectors, the fuel injectors are checked next. Violation of their performance leads to jerking of the car.

Injectors need to be cleaned periodically, in principle, like everything else.

Also, in an injection car, the functionality of all sensors involved in the operation of the power system is checked, and then the electronic control unit is checked.

avtoexperts.ru

From time to time, every car owner is faced with a situation where the vehicle begins to jerk when starting to move when pressing the gas pedal or driving at low speeds. This behavior of the car is often caused by not too serious disturbances in the operation of the internal combustion engine and other systems. However, they need to be diagnosed and eliminated as soon as possible. Otherwise, they can lead to a complex breakdown, which will take a lot of time and money to fix.

When can a car “jerking” appear and what are the causes of the phenomenon?

In the vast majority of cases, the symptom of unstable driving can be diagnosed in the following situations:

• While the vehicle is starting to move (pushing away).

• During slow driving at low engine speeds.

• If necessary, accelerate suddenly while driving on the road.

• While the power unit is operating at high speeds.

In addition, the described behavior of the vehicle may also occur in other operating modes. The reason for this may be malfunctions of the following systems and components of the machine:

1. System for supplying the fuel mixture to the combustion chamber.

2. Ignition system.

3. Incorrect operation of the transmission.

4. Malfunctions in the operation of the car's electronic engine control unit.

How to troubleshoot?

Let's take a closer look at the main and auxiliary systems of the car, which can cause the vehicle to “jerk” while driving. We will also focus on how to eliminate diagnosed problems.

Fuel mixture supply system

Quite often, the cause of unusual behavior of a car while driving is improper operation of the fuel supply system to the engine or the injection system of the air-fuel mixture into the combustion chamber. In other words, the internal combustion engine cannot obtain the required amount of gasoline or diesel fuel. As a result, there is not enough torque from the shaft to transfer mechanical force to the suspension, and you end up with a dip in power.

To get rid of troubles, you need to:

• Check the operation of the throttle assembly.

• Test the functionality of the idle speed sensors.

• Check the correct position of the throttle valves.

• Check the functionality of the mass air flow sensor.

In most cases, the defect is found in the injectors, which are responsible for injecting the fuel mixture. Less commonly, an uneven ride is associated with the air passages that connect the injector and the air filter. Depressurization is possible, which leads to loss of pressure.

The problem found can be corrected by replacing damaged parts. You can do this yourself, but it is better to seek help from service center specialists. After carrying out the work, it is important to additionally check the tightness of connections along all fuel and air supply lines.

If your car is equipped with a carburetor, you need to check the idle air valve and also make sure that the body of the device itself does not contain cracks, chips or other defects.

Ignition system

The next most common cause of a car “jerking” is a breakdown in the ignition system. This leads to the fact that the fuel mixture in the cylinders ignites at the wrong time. In addition, this may also occur due to the fact that low voltage current is supplied to the spark plugs. And the resulting spark is not enough for ignition to occur.

To diagnose faults you should check:

• Serviceability of spark plugs installed in the engine.

• Integrity of high-voltage wires going to the spark plugs.

• The performance of sensors that monitor the position of the camshaft and crankshaft.

Often, the car may jerk due to physical wear of the spark plugs or because the spark plug gap does not meet the required parameters.

Transmission

“Jerking” of the car can also occur due to the fact that the transmission elements are not operated in accordance with the technical regulations. This happens, for example, if the transmission fluid in the gearbox (especially automatic) has not been changed. And when the car’s mileage is 150-200 thousand km, it is necessary to repair the automatic transmission, otherwise the car will drive with slight jolts all the time.

It is better to carry out maintenance of such a complex unit as a gearbox only in a specialized center. You can take on work yourself only if you know exactly what needs to be done and how.

Accelerator

Let's deal with the situation when the “jerking” occurs due to too sharp pressing of the accelerator pedal. In this case, the engine sharply increases its speed, which can lead to improper operation of the vacuum ignition angle regulators. When the car moves at low speeds, the internal combustion engine distributor falls, which leads to shocks.

If the vacuum regulators do not work correctly when you press the gas pedal, the car engine cannot increase speed in time, and this, in turn, leads to problems with the operation of the throttle valve. As a result, the air-fuel mixture does not have time to burn, which damages the bearing, on which the ignition timing depends.

To diagnose the problem, you need to check the vacuum regulators. To do this, the hoses and pipes are disconnected, after which the holes are covered with hands. During operation of the internal combustion engine, you can clearly hear the retracting effect. If a vacuum does not form, the seal is broken and the unit should be replaced.

If your car moves jerkily, you should immediately identify the cause of the problem and fix it.

Let's go through the ignition system

The first thing that is checked in this system is the candles.

There have been cases when a car enthusiast replaced old spark plugs with new, and expensive ones at that, and ended up getting irritated due to the car jerking. But since the candles were new, he did not bother with them, but looked for a different reason.

This problem often occurs due to incompatibility of the spark plugs with the engine.

But their long-term use gives the same result. The spark plugs may fail, there will be gaps in their operation, and as a result, the fuel will not ignite well and may not burn completely.

In general, if the fuel system test fails, the next thing to check is the spark plugs. In this case, the candles themselves can suggest the cause of the malfunction.

At home, you should immediately check the gap on unscrewed spark plugs. Failure to do so will result in disruption of sparking. Then the spark plug is checked for sparking.

In a normally working spark plug, the spark should be powerful, purple in color and there should be no gaps in its appearance.

A faded orange spark, and even with gaps, will signal a malfunction of the spark plug or other element of the system.

Soot on the candle will tell you where the cause is hidden. If there is black carbon deposits on it, then either the ignition on the car is broken, or the mixture formation in the fuel system is disrupted, and this can already cause the car to jerk.

But you should not immediately, having determined that there are gaps and the spark does not correspond to the norm, blame the spark plugs for everything. It is quite possible that a weak spark is a consequence of a faulty connection in the system wiring or failure of one of the ignition elements.

Therefore, the second is to check all the wiring of the system for breaks, oxidation of contacts, and the presence of breakdown. And only after this the remaining elements are checked - the coil, the distributor, the switch.

About the transmission

Now a few words about the transmission, since it can also cause jerks when driving.

As you know, cars use manual and automatic transmissions.

As for a manual transmission, the gearbox and everything that follows it cannot cause jerking.

A manual transmission is a fairly simple design, and if it already breaks, it breaks specifically, and not creating jerks.

But the clutch can cause jerking. If it is heavily worn, in particular the driven disk, or “slips,” then the car easily begins to twitch.

But as a rule, jerking and twitching with such malfunctions occurs during gear shifting.

In automatic transmissions, the cause of the jerking is the gearbox itself.

It is very dependent on the quantity and quality of oil, so a lack of oil or its foaming can easily cause uneven running of the car.

You can measure the oil level in the automatic transmission using a dipstick.

Or without.

It all depends on the design of the automatic transmission.

How to measure the oil level in an automatic transmission.

Significant wear of the automatic transmission, as well as clogged oil channels, also causes the car to jerk at all speeds.

Gear shift

When your car jerks at low speeds, the transmission may be the culprit. Fortunately, there are few options here, manual or automatic. Let's divide the forerunners accordingly:

• Manual transmission:

1. something with a basket;
2. clutch disc wear;
3. breakage of the release bearing, etc.

• Automatic:

1. low level/poor condition of the “transmission”;
2. electronics fail.

In addition, if the jerk only makes itself felt when you slow down, the problem may be worn out brake discs.

Jerks on the gas

There are often situations when the car jerks when driving on gas, but everything is fine on gasoline. The cause may be problematic spark plugs or high-voltage wires.

But why then does the malfunction appear only on gas fuel?

The bottom line is that when using gas fuel, the breakdown requirements are higher than in the case of gasoline. It turns out that the spark follows the path of least resistance and, accordingly, not in the place where it is needed.

As a rule, this happens when the gas pedal is sharply depressed, when the mixture is lean for some period and it is during this period that the breakdown energy increases.

To confirm or refute the version, you can remove the spark plug and look at the condition of the white dielectric.

Sometimes the symptoms are visible directly on it, but there are situations when the breakdown occurs internally. In this case, the check is carried out only at the stand.

It happens like this:

1. Breakdown.
2. The spark plug does not “receive” a spark or the latter is very weak (we write in easy-to-understand language).
3. The fuel-air mixture does not ignite and the cylinder is excluded from the engine operation.
4. The power drops cyclically and the car starts to jerk.

After eliminating the malfunction in the ignition system, the jerking when operating on gas should go away.

Some car owners complain that after replacing all the ignition elements, nothing changes. But at the same time, they ignore the requirements of engine manufacturers about the permissible type of installed spark plug.

In some cases, reducing the spark plug gap may help.

There are also situations when gas and gasoline enter the same injector due to an error by the adjusters.

Plugs and wires are problem number one

One of the most common causes of unpleasant effects during car operation in the form of vehicle twitching is faulty spark plugs and high-voltage wires. Over time, spark plugs tend to deteriorate spark quality or fail completely. One set can last 100,000 km without problems, while the other will have to be replaced at 10,000 km. The health of the candles must be monitored as efficiently as possible, otherwise there will be a lot of problems and troubles.

The reasons for twitching may be the following:

• one of the spark plugs gives a bad spark, so under certain engine operating conditions the mixture does not have time to ignite and does not burn out, so one of the cylinders does not work correctly;
• the wire is broken, due to which the spark is not formed fully or not at all, the entire charge is lost on the way to the spark plug, which causes a number of troubles in the operation of the car;
• the candle is covered with brick-colored soot - this is a sign of the use of low-quality fuel, which led to the formation of metallized soot, which is conductive;
• due to malfunctions of the spark plugs and wires, the ignition coil began to fail and short out, this leads either to a complete stop of the engine or to operation on 2-3 cylinders;
• the spark plugs are simply old, the wear of the electrodes does not allow them to work normally, there are also various deposits and other unpleasant aspects, you just need to replace these parts.

This effect can occur if the machine has been idle for a long time. In this case, it is better to replace the spark plugs. Replacing the wires is not necessary, but you need to make sure they are working properly. If the electrical equipment is normal, you will have to dig further. Unfortunately, spark plugs and high-voltage wires are not the only possible cause of unpleasant effects. If you have replaced these parts, but still haven’t noticed any improvement in your ride, you will have to deal with the car’s electronics or perform other expensive procedures.

Vibration and jerking when reversing

There are situations when the car jerks while moving in reverse, and vibrations are also possible.

Here you need to consider which gearbox is installed.

If your car has an automatic transmission, you need to pay attention to the position of the engine protector.

It is possible that this element of the car was installed incorrectly when filling oil or performing other work. In this case, the exhaust pipe is close to the protection.

When you engage reverse, the engine tilts slightly, which causes vibration.

It is also necessary to pay attention that there are no touches along the entire perimeter.

If necessary, thick rubber seals must be installed.

There are also other possible reasons that are relevant for all cars:

1. Nedogazovka. It is necessary to take into account that the reverse speed is higher than the first, therefore, at low speeds (about 800-1200 rpm), twitching may appear, and the car itself does not have enough strength to accelerate. Almost the same principle applies here as with the second speed.
2. Poor contact. When moving backwards, the engine tilts a little. If there is a poor connection in the wiring, the situation gets worse when the reverse gear is engaged.
3. Suspension. Even in ideal condition, this component gives a certain vibration.
4. Severe wear on the differential.
5. Low-quality CV joints or “shifters”.
6. A worn clutch or some kind of defect if we are talking about a new car. More precisely, the basket presses the disc unevenly onto the flywheel.
7. Wedging in the basket.
8. Problems in the gearbox, namely the reverse gear.

Much depends on the car model. To determine a more precise cause, it may be necessary to check each of the presented versions. But it is better to contact experienced service station employees.

Automatic transmission

The situation when a problem with jerking occurs on an automatic transmission deserves special attention.

In this case, the following reasons are possible.

Control block

ECU malfunction is one of the causes of shocks when switching automatic transmissions.

Depending on the make/model of the car, the electronic unit can be independent or built into the “brains” of the engine.

To solve the problem, the ECU may need to be replaced.

Motor sensor

The cause of jerking when driving a car with an automatic transmission may be a malfunction of one of the control bodies, for example, or the mass air flow (MAF).

In such cases, the engine error may not light up. For example, on Ford Mondeo cars with a 6-speed automatic transmission, the problem may arise due to a breakdown that affects the change in torque.

Solenoids

Failure of these elements in the valve body often leads to jerking of the machine. In this case, the culprit is often the valve responsible for oil pressure.

Most often, it needs to be replaced to solve the problem. This situation is typical for automatic transmissions of the DP series (France).

Automatic transmission wiring harness

Wear or damage to this component causes many problems.

That is why during a major overhaul this unit is replaced first.

Mechatronics board

Some automatic transmissions have a separate unit that controls the solenoids. It is mounted in a tray, and if it breaks, it leads to many problems with the automatic transmission.

A similar component can be found in the Mercedes-Benz 722.9 with a seven-speed automatic transmission or in the six-speed “box” of the GM 6T30 and 6T40.

Hydraulic block

A decrease in oil pressure in the automatic transmission hydraulic system leads to jerking and may occur due to failure of the valve body.

The reason may be normal aging or bending of device elements due to overheating.

Problems with hardware

The worst thing is if the malfunction is caused by mechanical malfunctions of the transmission elements. In this case, disassembly and repair may be required.

For example, in Audi cars with a six-speed automatic transmission, the drum bushings often wear out.

As a result, oil is supplied to the friction pack, and due to lubricant leakage, slipping occurs, and the discs literally “burn”.

Other reasons:

1. Reduced oil level. It is enough to reduce the volume of lubricant by only 500 ml for twitching to appear.
2. Problems with automatic transmission and engine mounts. If there is excessive wear, the engine tilts, which causes jerking.
3. Overheat. The problem may arise when operating vehicles in hot weather when the radiators are dirty and the thermostat is faulty.

This list can be supplemented with a problem with the housing and wear of the band brake rod attachment point.

As a result, an oil leak appears and there is a decrease in pressure in the system, followed by a shock.

Mazda 6 owners faced a similar problem.

Automatic transmission Mazda 6

If difficulties arise in the operation of the automatic transmission, it is important not to delay repairs, but to immediately go to a service station for inspection.

If the cause of the car jerking in motion is mechanical problems, you will have to remove and disassemble the “box”.

But most often it does not come to this, and the issue can be resolved by restoring the electrical part.

Why is my car jerking at 50 mph?

Hello! The jerking reaction you describe may indicate a dirty or faulty MAF sensor.

This is a device that monitors the air intake and transmits this information to the ECM, which then adjusts the fuel supply. It could also be due to unstable fuel pressure or an ignition problem.

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Checking VAZ-2107 carburetor

Now let's take a closer look at how to identify the cause of such a malfunction on different car models.

The first will be the carburetor VAZ-2107; there are plenty of cases when the car suddenly starts to jerk while driving.

As already mentioned, you need to start checking with the fuel system:

• First you need to inspect all pipes of the system for cracks;
• Open the tank. It happens that in the summer the lid fits very tightly to the neck, blocking the access of air to the tank. When moving, the pump works and creates a vacuum in the tank, due to which the same pump is then unable to “pull” fuel. It seems like a small thing, but this also happens;
• Inspect the fuel filter located in the pipes leading to the fuel pump. These filters are transparent and easy to visually evaluate;
• You can also check the fuel pump without removing it. It is necessary to disconnect the pipeline coming from the pump from the carburetor and lower its end into some container. Then manually pump the pump into action and evaluate how it pumps fuel - it should supply it in even portions;

• While the fuel pipe is disconnected from the carburetor, unscrew the fitting on which the fuel line fits and remove the small mesh filter, clean it and reinstall it;
• Next comes the carburetor. It is advisable to remove it from the car, rinse it thoroughly, and inspect the accelerator pump membrane.

If actions with the fuel system did not help, we proceed to checking the ignition system.

• We unscrew the spark plugs, check their functionality, and replace them if necessary;
• We check the system wiring for breakdown. This can be done this way - in the dark or in a closed garage (the main thing is that it is dark), open the hood and start the engine. If there are voltage losses on the wiring, they will be immediately noticeable by the sparks that form. Next, we replace the wiring that “breaks through” and check the wire connections;

• Next, we check the distributor, there should be no signs of critical wear, it should be dry under the cover. Be sure to inspect the centrifugal regulator, and also check the vacuum regulator. You should check whether there is a vacuum in the pipe leading to it.
• Then the Hall sensor, coil and switch will be checked for functionality. You can do this yourself if you have the necessary equipment at hand, but you need to know how to check them. But you can contact an auto electrician.
• It is also important not to forget to check that the ignition is installed correctly.

This is in general and all the features of identifying the cause of uneven running on the VAZ-2107.

Checking VAZ-2110

Let's move on to a more modern car - the injection VAZ-2110, which can also twitch when driving.

It’s also worth starting the check with the power system, but it is carried out somewhat differently than on the “Seven”:

• Start with the fuel filter and pump. The filter there is non-separable and diagnostics are done by checking the performance of the pump. It is impossible to carry out the work at home; it is better to contact a service station. There, a special device is connected to the outlet of the fuel filter to measure the outlet pressure. If the pressure does not correspond to the norm, then another measurement is taken, but the device is connected to the fuel pump before entering the filter. This way it is determined whether the insufficient fuel supply is due to the filter or the pump;
• Then the functionality of the injectors is checked. If everything is in order with the specified elements, then the check of the electronic component begins;
• First, all sensors are checked for serviceability and functionality; if they are serviceable, then all that remains is to check the control unit;
• The control unit can often cause jerking if its firmware is broken, that is, it does not operate in the mode it should.

  
  Usually such a malfunction is “cured” by “reflashing”, but if there is internal damage in it, then it is replaced.

As for checking the ignition system, it is in many ways similar to checking the VAZ-2107 system.

It all starts with the spark plugs, then the wiring is checked, then all the components, but taking into account the fact that this system is controlled by an electronic unit that controls the operation of the engine using sensors.

So, when checking the ignition, you will also have to check the performance of the sensors and the unit itself.

VAZ 2114 injector

Owners of VAZ 2114 cars with an injector often complain about the appearance of car jerking and loss of traction. The first thing you need to do is connect to the diagnostic connector and look for errors.

The most common problems that may occur are:

• P0327 - knock sensor, low voltage;
• P1602 - unstable voltage;
• P2127 - gas pedal position sensor, low voltage;
• P2138 - gas pedal position sensor, signal mismatch.

In this case, you need to look at what error Check appears. Most often this is P2127, so this is what you need to pay attention to.

After connecting, you need to look at the information that the sensors provide when you press the gas.

If after pressing the accelerator the indicators change significantly, this may indicate a violation of the resistive layer.

The following steps may be required to resolve the issue:

1. Take off the gas pedal.
2. Loosen the mounting screws.
3. Remove the cover.
4. Wipe the circuit with an alcohol solution.
5. Reassemble the pedal and put it in place. Don't change your position.
6. Take measurements using a potentiometer.

If the data is static, and after releasing the gas the voltage parameters do not change, this indicates a solution to the problem.

Also look at the knock signal for different cylinders. If any of them has a low parameter, this may indicate a problem with the sensor and the need to replace it.

What's the result?

Taking into account the above information, it becomes clear that if the engine jerks during acceleration, it is not always possible to quickly determine the problem. The culprit of the problem can be either simple things (dirty injectors, faulty spark plugs or spark plug wires, bad gasoline, clogged fuel/air filters), or more serious problems.

Additional data and observations from the owner himself make it possible to quickly localize and then efficiently eliminate the problem, both when contacting experienced specialists and as part of independent repairs.

As a result, jerks and dips appear when accelerating, and the car jerks in motion during transitional conditions. Causes and troubleshooting.

The reasons why, after pressing the gas pedal, dips occur and the engine begins to choke. Gas engine failures when switching from gasoline to gas.

The engine twitches at idle: why does this happen? Engine jerking in idle mode, diagnostics of possible malfunctions, recommendations.

What to do if the car accelerates worse, does not pick up speed, or has failures during acceleration. Why the engine does not pull, how to find the reason for the decrease in power.

Lada Kalina, VAZ 21099

When operating the Lada Kalina, jerking may occur when driving. They can occur when starting off, during acceleration, or during normal driving.

In most cases, to identify the cause, you need to diagnose the ECU at a service station, but there are situations when you can solve the problem yourself.

Below we will consider possible solutions for different situations that can be applied to other cars, for example, VAZ 21099 injector.

When starting to move

The reason is the slow response of the engine to pressing the accelerator. A jerk appears at the moment the throttle opens, when the sensor of this unit transmits information to the ECU.

Next, the electronic unit determines the moment of transition from the idle mode to the load and makes a decision to add fuel.

When there is a shortage of pressure in the fuel supply system, jerking occurs.

During acceleration

Here the reason is the same as in the case discussed above. When you press the gas, due to lack of pressure, less fuel is supplied to the engine than necessary.

While driving

Such problems are often caused by breakdowns in the ignition system. To check the version, do the following:

• open the hood;
• turn off the ignition;
• check the quality of the wires;
• start the engine and listen to it for the presence of a crackling sound/breakdown;
• change the spark plugs and inspect their condition, and if problems are identified, make repairs.

The cause of jerking when driving the Lada Kalina may be a breakdown of the sensor that displays information on the throttle valve.

The problem can be identified by uneven operation of the motor and a decrease in its power. The only way out in this case is to replace the faulty element.

Summarizing

So, the main reasons for a car jerking during acceleration are listed above. Let us add that in turbocharged engines it often appears due to a defective turbine. In particular, incorrect pressure regulation due to a bad solenoid valve or a non-functioning electronic actuator. Which is solved by replacing the component in the first case and the entire assembly in the last.

Thus, when you twitch by pressing the gas, you should start checking with the power supply, weeding out serviceable elements and smoothly moving to the main computer. It takes time to work independently and you need to have a good understanding of automotive systems. But why rack your brains when you can turn to trained professionals for help? A convenient solution is the Uremont online platform. One resource where you can immediately access all car services nearby within Russia, Kazakhstan and Belarus.

Opel Astra

A common problem is the appearance of jerking while driving an Opel Astra. In this case, the malfunction most often appears after the engine has warmed up to 50 degrees Celsius.

The first thing to do is to carry out diagnostics and count errors. During the assessment process, it is necessary to look at the injection timing and EGR sensor/valve performance.

After that do the following:

1. Warm up the engine to operating voltage.
2. Check the voltage at the EGR contacts (there are five in total). To solve this problem you need to use needles. There should be about 14 V on the outermost contacts, about 5 V on the second one from the windshield, and on the third one there should be from 0.65 to 2.0 V.

3. Check the wires that go to the EGR.
4. Make sure the valve is intact. Perhaps it has malfunctioned.
5. If the valve and wires are intact, only the ECU remains. It is necessary to open the block and see what problems there are.

Checking Ford Focus

The last car will be the Ford Focus 3 injector, which is not surprising, but it can also twitch when driving.

Note that the sequence of checking the ignition and power systems on this car has the same algorithm as on the VAZ-2110. But let’s assume that our car is equipped with an automatic transmission, and no problems were found in the engine systems.

As for checking the automatic transmission, you can only check the oil level yourself, but you need to know how to do it correctly.

A more in-depth check can only be done on the service. There, using special stands, they will first check the performance of the engine, and then diagnose the operation of the automatic transmission.

Also read about the reasons why.

What are the signs that your transmission is stopping?

Transmission Trouble: 10 Warning Signs That Need Repair

• Refusal to change gears. If your car refuses or struggles to shift gears, you are most likely experiencing a problem with the transmission system. ...
• Burning smell. ...
• Neutral noises. ...
• Slipping. ...
• Stretch coupling. ...
• Liquid leak. ...
• Check engine light. ...
• Rubbing or shaking.