P0300 – Engine Misfire Detected

The P0300 diagnostic code is yet another “It could be anything” code. But once you take away whats not wrong with the car the majority of the time the problem ends up being decently simple to repair. Here is a list of some of the causes of a misfire code. Its not a list of everything but will usually get you on the right track. Sometimes a random misfire happens once or twice and stops, If your lucky you can just clear the code and it won’t come back…… Use good fuel. These possible causes can be used to troubleshoot any misfire code.



  1. camshaft position sensor bad or shorted

  2. Bad and or damaged coil or coil pack

  3. Bad EGR valve (leaking gasket, stuck valve, blocked tubing or passages

  4. Bad fuel injector or Injector going bad or clogged injector

  5. Damaged or burned exhaust valve

  6. Damaged or clogged catalytic converter/s

  7. Faulty or worn oxygen sensor/s

  8. Worn.damaged, dirty spark plugs

  9. Spark plug wires in wrong firing order

  10. Damaged or bad spark plug wires

  11. incorrect spark plugs (non OEM)

  12. Fuel too lean (low fuel pressure)

  13. Loose battery terminal

  14. low battery voltage

  15. Clogged fuel filter

  16. Low compression in 1 or more Cylinder

  17. Leak in Intake manifold

  18. Leak in exhaust manifold (missing bolts?)

  19. Engine slightly overheating

  20. Fuel is contaminated


Common causes of OBD2 Code P0300,P0301,P0302,P0303, P0304, P0305, P0306, P0307, P0308