If you notice that your car jerks when you driving it, this can have different reasons. There can be many different causes or defects behind the jerking. We’ll tell you exactly what they are and what you should do in any case. As always, we also have helpful tips and tricks at the ready. Find out why your car might jerk while driving by reading on!
Car jerks when driving – Don’t panic
You are driving to work, shopping, or visiting friends, and all of a sudden, your car starts to jerk while driving. It is understandable that at first, panic breaks out. Usually, however, the latter is unjustified. There can be several reasons for this. If you take care of it right away, you won’t have to worry about any serious consequences. What can cause the jerking, we explain to you now!
Check the ignition coils or the ignition distributor
The cause of a bucking car can also be a loose cable. As soon as it is not plugged in properly, there is a misfire – and the car jerks. There are different places on the entire ignition system where you can check for faults, such as the ignition coils or the ignition distributor on older cars.
The ignition coils or distributor sits in a different spot on every car. Therefore, it is best to trace the ignition wires away from the engine. There, where they end, are usually also the ignition coils, respectively the distributor. In rare cases, it can also happen that the ignition coils are located on the individual spark plugs.
Once you have found the desired component, you must first disconnect the ignition cables from the plugs. After that, you can easily unscrew the coils.
Now you can check the contacts of the coils or the distributor on the front and back for corrosion. If the connections are oxidized, you need to clean them. The best tool for this is the DIY tool “Dremel” of course, any other tool that grinds the contacts free will work. After grinding, it is best to spray the contacts of the coils with WD40 to keep the connections free of corrosion for as long as possible and ensure good electrical conductivity.
If cleaning the coils or the distributor has not helped, replacing the parts in question will also help.
Electronics can be very susceptible to faults – it is best to check the relays for the ignition. The fuse box is usually located in the driver’s footwell, but there is often a second fuse box in the engine compartment. Clean the contacts of the relays and plug them back into the same places as before.
Car jerks while driving: check the ignition cables
An incorrectly plugged cable can also be the root of all evil and lead to a jerky car. However, the check is quite simple. First, check whether all ignition cables are correctly and firmly in place. If they are not, this is often where the fault lies, as the spark plug is not getting any current, and the cylinder in question is unable to fire.
To make things as easy as possible, it is best to remove the ignition cables to check for visible damage completely. It is important to remember which cable is on the ignition coils or spark plugs. If you mix up the cables, this can have significant consequences, and it is best to number the cables.
You can often detect internal damage to the graphite cable by carefully feeling it.
Again, the contact points to the spark plugs, or the coils may be oxidized. However, since these are not easy to clean, it is not worth it in most cases. A new set of ignition cables costs around 25 euros, depending on the model and brand.
Car jerks when driving: Check mass airflow sensor
In order for the engine to function properly, the correct air-fuel mixture is important – the air mass meter measures the intake air content. If the measured values are not correct, either too much or too little fuel is injected, resulting in incomplete combustion, engine judder, and loss of power. What could be the reason for this? There are various causes for distorted values:
- On the one hand, the mass airflow sensor may simply be dirty. In this case, it is sufficient to clean the mesh of the mass airflow sensor.
- It is probably defective if it is not due to a dirty air mass sensor. Then you should change the mass airflow sensor.
- In order to determine a defect in the mass airflow sensor, you should read out the fault memory. If you do not have a suitable self-diagnosis device in your own workshop, you should visit a specialist workshop to have the fault memory readout.
- However, you should be careful when reading out the error memory yourself: Often, the error memory indicates that there is a defect in the lambda sensor, although the mass airflow sensor is actually broken and provides incorrect values.
By the way, a dirty or defective throttle valve can also cause your car to jerks when driving. Another cause is usually a lambda sensor defect.
Bad fuel supply leads car jerks when driving
If the jerking frequently occurs when accelerating, the following culprits are possible:
- Insufficient fuel supply. This can either be a defect in the fuel delivery unit or the fuel filter.
Pro tip: You can also change the fuel filter yourself – we’ll explain how in another article. For this, you only have to click on the previous link!
- If you cannot determine the exact reason for the jerking yourself, you should visit a specialist workshop.
In rare cases, the dual-mass flywheel is broken and is responsible for the jerking. This is because the flywheel normally dampens the engine’s vibrations so that they do not reach the drivetrain and transmission.
You can rule out the above causes, but it is still there: The car jerks when shifting gears. Read on to find out what else could be causing this! Ready to go? Then go directly to the next section!
Car jerks when driving: Check the spark plugs
If you have now removed the ignition cables, you can take this opportunity to check the contacts on the spark plugs directly.
Loosening or unscrewing them is a bit more complicated and requires a bit of intuition. You often need a special spark plug socket, which must have the right size depending on the size of the spark plug. If you can’t loosen it directly, a little WD40 will help.
If you have removed the spark plugs, you can usually tell the naked eye what condition the plugs are in. As you can see in the picture, the left spark plug is not usable. Here, the ignition cable was not properly plugged in, which resulted in not firing properly.
If you can’t see any more severe signs of use, you can clean the contacts of the spark plugs, as you did with the coils. If you your car jerking while accelerating read our another guide >> Car jerking when accelerating: Possible causes & solutions
Car jerking when shifting because of the clutch
We won’t keep you in suspense any longer and will explain in a nutshell what causes the car to jerk when shifting gears:
Did you know? If your car jerks when you shift gears manually, there is not necessarily a defect. Driving errors are often behind it: Have you possibly engaged the wrong gear or given too little gas when shifting or starting? If this is not the case, you should visit a workshop to find the cause of the jerking.
What could be the cause of this? For example:
- The slave cylinder is defective.
- The clutch release bearing is broken.
- In rare cases, the dual-mass flywheel is broken and causing the jerking.
- This normally dampens the engine’s vibrations so that the latter do not reach the driveline and the transmission.
By the way: If the entire clutch is defective and it jerks, your car will jerk when you change gears. In this case, you should change the clutch. Do you want to know more? Just click on the corresponding link!
None of the above scenarios apply to you? Your car jerks when braking? We cover that too: read on to find out the possible reasons!
Car jerking when driving: Other causes
The steering wheel vibrates, and the car jerks, especially when braking… several causes can be responsible for this. What are they? We’ll tell you now:
Tip: The first suspect is, of course, the brake discs. And you’re not far wrong: When brake discs overheat, it leads to jerks when driving. But worn tie rod ends can also be to blame. If this is the case, you should change the tie rod ends. To learn more about the respective topic, you only have to click on the corresponding link – this will take you directly to the appropriate blog post!
Besides the brake discs and defective tie rod ends, other causes can also be responsible for the jerking during braking:
- An imbalance in the tires can also cause the car to jerk when braking.
Good to know: An imbalance not only affects the handling of your car but also tire wear. You can find out more about this with just one click!
- If the ABS indicator light in your car also lights up, you can be sure that your car is juddering because there is a problem with the anti-lock braking system.
- If you can see the following symbol light up in your cockpit, you should always visit a workshop to discover the cause.
Why does the car jerk in cold weather?
In winter, the car may start to jerks when driving or accelerating. Often it is due to the fuel or the engine oil. Usually, engine oil is thin and smooth. In cold weather, the engine oil is more viscous, so it is harder to get to all the places. The number in front of the W (e.g., “5W-30”) describes the oil’s flow characteristics: the higher the viscous in cold conditions. The lower the number, the faster the oil can reach all points, even cold weather.
Tip: In winter, don’t rush the car right away, but slowly bring it up to operating temperature. If the car bucks in winter, it may also be due to the fuel. Fuel must evaporate in order to be ignited. In cold weather, fuel does not evaporate as well, so combustion is no longer ideal.
In addition, the fuel-air mixture ratio must be right. Condensation forms in the intake tract and on the cylinder wall in cold conditions. This briefly affects the air/fuel ratio. After a few minutes of driving, the jerking should subside.
But that’s enough talk from us – it’s your turn now! Does your car jerks when you driving? What is the reason? Did you go to a garage, or did you fix it yourself? Tell us about it in the comments!