Why is my car juddering, jerking or stuttering and what should I do?

Why is my car juddering, jerking or stuttering and what should I do?
Does your car hesitate or stutter while you’re accelerating or pulling away? Are you feeling engine judder when your vehicle is idling at the traffic lights? 

There are various reasons why you'll experience car stuttering or jerking, which can make it tricky to diagnose the problem if you’re not an expert.

Many causes of car juddering or hesitation are not serious and can be fixed quickly and cheaply. However, on occasions, car stuttering when accelerating can be a sign of a problem with your car and result in a trip to local garage or a visit from a mobile mechanic. 

In this know how guide, we look at some of the most common reasons why your car might shake, judder, jerk or stutter and what you should do when it happens.

Why is my car juddering when accelerating?

If your car jerks and shudders when accelerating at low speeds then it could indicate a serious problem with your vehicle.

There can be a number of possible reasons why your car jerks while accelerating:

  • Spark plugs: 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. 
  • Fuel injectors: Dirty or malfunctioning fuel injectors can disrupt the fuel delivery and result in the vehicle stuttering or jerking at low speeds.
  • Fuel filter: A clogged, or worn-out fuel filter can impact fuel delivery and result in performance issues, particularly at low speeds.
  • Catalytic converter: 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. There may also be a rotten egg smell.
  • Transmission fluid: Contaminated or low transmission fluid can impact acceleration, especially if the fluid is very old and dirty.

How to fix car juddering when accelerating

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.

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Why is my car juddering when pulling away?

If your car judders, shakes or stutters when you are pulling away in first gear then it may be 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 car juddering when pulling away

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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Why is my car juddering at low revs?

Car judder at low revs can be extremely irritating. The problem will usually appear at low speeds, before vanishing as you change into the higher gears.

Possible causes for juddering at low revs include:

  • Distributor cap: Moisture in the distributor cap can make a vehicle jerk when accelerating at low speeds or low revs. 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. 
  • Engine mounts: 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 car juddering at low revs

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.

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Why is my car juddering when idle?

car-juddering-shaking-idle

Does your car's engine judder when idling at traffic lights and junctions, and sometimes feels like it’s going to stall? It could be a fault with the spark plugs or a build-up of dirt and grime.

A clogged filter or fuel injection system can also 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 car juddering when idle

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.  

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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.

Why is my car 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. 

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 car juddering when driving at speed

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.

Why is my car juddering when braking?

The reason why your vehicle is shaking when braking may be 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 car juddering when braking

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.

Why is my diesel car juddering when driving?

Having a diesel-powered vehicle comes with its own set of potential issues – and having a juddering car is a common problem. The most common reason why your diesel car is juddering while you are driving is due to clogged fuel injectors.

How to fix diesel car juddering when driving

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.

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 car tyres that cause juddering

Get your vehicle wheels realigned or your tyres replaced. This can be very easily done by heading over to RAC Tyres.

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