Fuel injectors are a key part of petrol and diesel engines. Dirty, faulty, or failing fuel injectors can result in poor acceleration, increased fuel consumption and rough idling.
In some cases, a failing or faulty fuel injector will prevent your car from starting. That is why it’s important to be aware of the warning signs that indicate your fuel injectors need replacing.
In this car maintenance guide, we explain how fuel injectors work, common problems, and how much they cost to replace.
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How much does it cost to replace a fuel injector?
According to the latest data, the average cost to replace a fuel injector in a car in the UK is around £185.
However, this can vary due to a variety of factors, including the make, model, age and engine size of the vehicle.
The condition of the area in and around the fuel injector can also impact the final price you pay for replacement.
Source: whocanfixmycar, April 2026
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Fuel injector replaced cost by manufacturer
Here are the average prices you will need to pay to replace your fuel injector for each of these brands:
Manufacturer | Average Cost |
Audi | £250 |
BMW | £172 |
Citroen | £229 |
Ford | £169 |
Mercedes | £164 |
MINI | £130 |
Nissan | £220 |
Peugeot | £197 |
Renault | £132 |
Toyota | £200 |
Vauxhall | £165 |
Volkswagen | £224 |
Volvo | £172 |
Source: whocanfixmycar, July 2026 (prices rounded to nearest whole number)
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What is a fuel injector?
A fuel injector is a precision part in an internal combustion engine that delivers fuel into the cylinders in a controlled spray, generating the power to move the vehicle.
Its job is to supply the right amount of fuel at the right moment to ensure efficient combustion.
Instead of relying on older carburettor systems, modern injectors use electronic control to adjust fuel delivery based on factors such as engine speed, vehicle load, temperature, and throttle input from the driver.
Compared to a carburettor system, the fuel injector improves power, reduces emissions and enhances fuel efficiency.
Each injector contains a nozzle and valve that open and close rapidly, creating a mist that mixes evenly with air that is also sent into the combustion process.
Correct and consistent fuel injection is essential for smooth running and engine performance in both petrol and diesel vehicles.
Common fuel injector issues
Here are the most likely problems you could see with a fuel injector in your vehicle:
- Clogged injectors: Dirt buildup restricts fuel flow
- Leaking injectors: Worn seals or cracks allow excess fuel into the engine
- Electrical faults: Wiring or connector problems stop the injector from firing correctly
- Injector stuck open or closed: Leads to too much or too little fuel entering the cylinder
- Poor spray pattern: Wear or deposits prevent proper distribution of fuel
- Fuel contamination: Water or debris in the fuel can cause internal damage
- Faulty o‑rings: Causes fuel odours, rough running or visible leaks
Any of these problems can lead to misfiring, uneven distribution of power and lower fuel economy.
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