10 reasons why your car jerks when accelerating at low speeds

Unfortunately, there are many causes for a car to start shaking and vibrating when you are travelling at low speeds when out on the roads.

Some are down to poor car maintenance – while others are a result of damage to the vehicle.

In this latest driving advice article, we share the main reasons why your vehicle may be accelerating when you are at a slower speed.

1. Worn spark plugs

One of the most common causes for a car jerking is that spark plugs are old or worn out, meaning that they can cause incomplete combustion.

As a result, this leads to a car engine misfiring and jerking during acceleration or when travelling at low speeds.

This simplest way to fix the problem is to replace the spark plugs, which will ensure a smoother, more consistent combustion process.

2. Gearbox problems

Jerking during acceleration can occur if there's an issue with the gearbox or the fluids that keep it in full working order.

This can include low transmission fluid. It is important for all car owners to regularly top up fluids where necessary in a vehicle.

Although there is an extensive list of potential issues with a gearbox – many of which will require the help of a mechanic – in some cases all that is needed to inspect the area and top up with fluid.

3. Poor quality or wrong fuel

If drivers use poor-quality or contaminated fuel then it can cause incomplete combustion or irregular fuel flow, leading to jerking when accelerating.

This is also the case if the driver puts the wrong fuel in the car.

If this has happened, then you’ll need to call out your breakdown cover provider and get the issue sorted.

For future reference, if they are able to, then then need to use high-quality fuel. It can also help to clear dirt and debris from around the fuel cap.

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4. Faulty fuel pump

A failing fuel pump may not supply enough fuel to the engine, causing it to stutter or jerk when you press the accelerator.

This will require a professional’s help, as the solution to this problem is to replace the fuel pump.

Much like the other fuel-related problems, regularly cleaning the surrounding area and having an annual service will help extend the life of the fuel pump.

5. Overheating engine

If your engine is running hot – and your check engine dashboard warning light has appeared – then it could be the result of an overheating.

This situation can cause the vehicle to lose power and jerk while accelerating. However, it is important to stop the vehicle as safely and as soon as possible.

Engine overheating can be caused by low coolant levels, a failing thermostat, or a broken water pump – amongst several other causes.

It is important for drivers to ensure the engine cooling system is functioning properly by checking the coolant levels and inspecting the radiator, thermostat, and water pumps regularly.

6. Clogged air filter

Air filters can get choked by dirt and debris over time, and this can restrict the airflow to the engine.

As a result, this can lead to poor performance and jerking, especially during acceleration and at low speeds.

This is why it is vital that they are regularly replaced to allow proper air intake for the engine to function efficiently.

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7. Blocked catalytic converter

The exhaust emission control device can sometimes get blocked over a long period of time.

This is especially the case if the catalytic converter hasn’t been serviced in a few years.

Although this is something a car owner can do themselves, it is a vitally important piece of machinery – so if they are unsure, they should take it to a mechanic. This is because the part will need to be removed to then be cleaned.

8. Damaged engine cylinders

If an engine cylinder is damaged, it will need to be replaced.

Should any cracks appear, then it will lead to pressure issues, reduced performance and jerking when accelerating.

In some cases, there valves around the cylinder can malfunction, and this can result in the same symptoms.

9. Worn or slipping clutch

For drivers of manual vehicles, a worn or slipping clutch can cause jerky acceleration, especially when starting from a stop or shifting at low speeds.

If the clutch is worn or damaged, it may need to be replaced to restore smooth shifting.

There is also a common issue with fluids leaking which can further damage the clutch. This is something else that will result in a mechanic to get involved and make the required fixes.

10. Engine Control Unit (ECU) malfunction

The ECU is responsible for managing engine functions, including fuel and ignition.

However, if the ECU is malfunctioning or has corrupted data, it can cause jerking or stalling during acceleration.

A mechanic will need to carry out a diagnostic check and then make any necessary fixes. A lot of these problems can result in a car jerking while accelerating.

They will then carry out an ECU reset, and the vehicle should return to normal.