There are various reasons why you'll experience your car jerking, which makes it tricky to diagnose the problem if you’re not an expert.
To help you understand the cause of that worrying movement you’re feeling behind the wheel, we look at some different scenarios and what you should do when faced with them…
Car juddering when accelerating
My car jerks and shudders when I press down on the accelerator but stops when I take my foot off the pedal.
What could the problem be?
An acceleration problem is usually the result of insufficient fuel, air, or spark during the combustion process.
Worn-out spark plugs or the electrical cables attached to them are one of the most common causes of cars stuttering. A deficient spark plug causes the engine to misfire, making your car jerk when you accelerate.
The engine may also be much noisier than it normally is, sounding more like an aeroplane taking off than a car.
A clogged catalytic converter is another reason why a car jerks while accelerating, as a blockage can disrupt the exhaust system’s airflow.
When you press down on the accelerator pedal, you may notice a delay in your car’s response, followed by a sudden jerk or lurch forward. There may also be a rotten egg smell.
How to fix it
If the issue is something as straightforward as faulty spark plugs, you may have the know-how to change them yourself. You may also be able to unclog minor blockages with a good catalytic converter cleaner.
But if you don’t understand the mechanics of your car very well or it’s a more serious blockage, it’s best to seek expert help.
Check out our RAC Approved Garage Network to find a mechanic you can trust. It only includes garages that provide quality work and exceptional customer service, giving you peace of mind if your car needs attention. Most repairs can even be carried out by a mobile mechanic right on your driveway.
Car juddering when pulling away
When I set off in first gear, my car sometimes stutters and shakes until I put it into a higher gear.
What could the problem be?
The most likely reason that a car jerks when accelerating from stop is a problem with the clutch.
It could be due to worn-out friction material or a pressure plate defect (or combination of both). It could also be caused by an oil leak contaminating the clutch plate.
How to fix it
If there is a fault with the clutch, you will need to find out whether it’s a mechanical issue or whether the clutch facing has been contaminated. This is best left to a professional to deal with.
Replacing a clutch is a specialised repair, so take your car to a reliable garage to get the work carried out.
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Car juddering at low revs
My car is very shaky and jerks when I accelerate at low speed but is fine in the higher gears.
What could the problem be?
As well as some of the causes of car stuttering mentioned earlier, moisture in the distributor cap can also make a vehicle jerk when accelerating. If your car is parked overnight in cold temperatures, condensation can form inside the distributor cap, causing the engine to misfire when accelerating at low speeds.
Another possibility is a problem with the engine mounts, which hold the engine in place to the chassis. A mounting that is loose, worn or broken will cause your car to vibrate at low revs.
How to fix it
Parking your vehicle in a garage or outside porch will help to prevent moisture from forming. If you have to park your car on the street, a thermal cover can help to reduce the risk of condensation.
If the engine mounts need replacing, we recommend getting an approved mechanic to do this because the engine needs to be securely supported from underneath while it’s being fixed.
Car juddering when idle
My engine judders when idling at traffic lights and junctions, and sometimes feels like it’s going to stall.
What could the problem be?
Along with faulty spark plugs, a build-up of dirt and grime is the likely cause of cars stuttering when idle.
A clogged filter or fuel injection system can starve your engine of fuel or oxygen, causing your car to judder and shake.
As a car ages and racks up thousands of miles of wear and tear, its valves can become blocked with sludge. If your engine doesn’t get an even and continuous distribution of clean fuel, it can start to shake or shudder while it idles.
If the judder only happens when idling, it could be a small leak on the vacuum side of the engine, or a worn-out electrical component such as the crankshaft sensor.
How to fix it
Unless you’re a professional mechanic, don’t attempt to replace components yourself. Your garage can have a look under the bonnet and run diagnostics tests to find the root cause of the problem.
Book an MOT with the RAC today
As a preventative measure to keep your car running smoothly in future, regularly check your engine for signs of dust and dirt clogging up the system, and make sure you have your car serviced once a year or every 10,000-12,000 miles.
Occasionally, things do go wrong while you’re out on the roads, so be sure to have the correct breakdown cover in place just in case.
Juddering when driving at speed
If you are heading down a motorway or A road a speed and notice your car shaking and stuttering, then you could have an issue.
What could the problem be?
There are a range of reasons why your car is juddering when you accelerate. Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
How to fix it
If it is just a bit of dirt or some moisture, then the best thing to do is clean the areas in question and apply the necessary lubricants.
However, if it is a more serious issue, then you will need to see a mechanic to get it fixed.
Over time some parts of your vehicle will need replacing, so visiting a trusted garage is key.
Juddering when braking
You notice your engine stuttering as you apply the brake and while you slow to a stop – sometimes leading you to stall the vehicle.
What could the problem be?
The reason why your vehicle is shaking when braking is due to the uneven thickness or the deformation of the brake disk. In order for the brakes to be successful, there needs to be a uniform thickness of the disk to avoid unwanted friction.
How to fix it
If you catch this issue before it gets worse, you can clean both the disk and the surrounding surface – however, this is a temporary fix and after some time they will need replacing.
Should the disk be damaged, it can be very dangerous to drive your vehicle. Get it replaced as soon as possible.
Diesel car juddering when driving
Having a diesel-powered vehicle comes with its own set of potential issues – and having a juddering car is one of them.
What could the problem be?
The most common reason why your diesel car is juddering while you are driving is due to clogged fuel injectors.
How to fix it
This is a relatively easy fix. Remove the fuel injectors, give them a clean, wipe around the area they sit in the vehicle, insert the injectors, and then restart the vehicle.
Can distorted car tyres cause juddering?
Throughout the time you own a vehicle, you are more than likely to suffer from issues with your tyres. One of the side effects of this is your car jerking and stuttering.
What could the problem be?
Most issues that impact your wheels and tyres can lead to your car juddering. If you have incorrect tyre pressure or balance, then it can lead to uneven tyre wear or damaged tyres. This all leads to juddering.
Over time, this can also lead to loose lug nuts which can also lead to juddering.
How to fix it
Get your vehicle wheels realigned or your tyres replaced.
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