Car's ECU detects disbalance of the engine working cycle parameters, usually variations of crankshaft revolving speed, that caused by random/multiple misfires in engine cylinders. P0300 indicates generic error with undefined cylinder. P030x (where x=1,2,3,...) points exact number of cylinder with detected misfires.


  • Check Engine dashboard light is ON
  • Unstable work and sound from engine: stumbles, shakes
  • Possible lack of power and car dynamic, engine shakes when accelerating
  • Could be issues with engine start


  • Faulty or worn-our spark plugs or connectors
  • Faulty coil
  • Faulty fuel injector
  • Low fuel pressure
  • Exhaust system issues
  • Low quality of the fuel

Severity - Major

Need to be fixed ASAP. With a time could lead other systems malfunctioning and increasing of repair casts.


  • Be sure using a quality fuel. If not, change fuel, clear code and wait few days driving if it re-appears.
  • Check spark plugs and coil connectors and wires, replace, if required
  • Visually inspect spark plugs, replace, if required
  • Review and correct, if required, fuel injectors, distributor cap, compression, other systems that have DTCs.