P0300 Misfires in several cylinders
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.
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