Ignition and misfires

P0300 Misfires in several cylinders

By: Diagno editorial team · Updated: 2026-10-15

P0300 means: Misfires in several cylinders. The engine computer noticed that fuel in a cylinder sometimes doesn't burn. Don't drive until the car has been checked. The engine could be damaged. The repair usually costs about €40–600 in Estonia. The most common cause: old spark plug.

Is it safe to drive?Don't driveDon't drive until the car has been checked. The engine could be damaged.

Typical repair cost€40–600parts and labour in Estonia

What it means

The engine computer noticed that fuel in a cylinder sometimes doesn't burn. The engine then runs rough and jerks. When several cylinders misfire, the cause is often shared: an air leak, fuel, or old spark plugs. If the engine light is flashing, unburned fuel can ruin the catalytic converter in a short time.

What could be wrong

1Old spark plug
2Faulty ignition coil
3Clogged or leaking injector
4Air leak
5Low compression

What you can check yourself

Swap that cylinder's ignition coil with the neighbouring one and clear the code. If the misfire follows the coil, the coil is faulty. You can check the simple things yourself, but the repair is best done in a workshop.

How we fix it

We check the spark plugs and ignition coils
We check the injector and look for air leaks
If needed, we measure compression

Standard SAE description: Random/Multiple Cylinder Misfire Detected

This code usually comes with: Check engine lightSee what the light means →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

Book a diagnostic check

Questions

What does fault code P0300 mean?

Misfires in several cylinders. The engine computer noticed that fuel in a cylinder sometimes doesn't burn. The engine then runs rough and jerks. When several cylinders misfire, the cause is often shared: an air leak, fuel, or old spark plugs. If the engine light is flashing, unburned fuel can ruin the catalytic converter in a short time.

Can I drive with code P0300?

Don't drive until the car has been checked. The engine could be damaged.

How much does it cost to fix P0300?

Roughly €40–600 in Estonia. The price depends on exactly what has failed and on the car.

How is P0300 fixed?

We check the spark plugs and ignition coils. We check the injector and look for air leaks. If needed, we measure compression.

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.