- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure

The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"

The control module monitors the crankshaft speed and has detected a misfire condition

- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

P0300 INFINITI
P0300 CHRYSLER
P0300 BMW
P0300 DODGE
P0300 JEEP
P0300 FORD
P0300 HONDA
P0300 MAZDA
P0300 HYUNDAI
P0300 ACURA
P0300 MITSUBISHI
P0300 NISSAN
P0300 SUBARU
P0300 TOYOTA
P0300 SCION
P0300 LEXUS
P0300 AUDI
P0300 VOLKSWAGEN
P0300 BUICK
P0300 CADILLAC
P0300 CHEVROLET
P0300 GMC
P0300 PONTIAC
P0300 SATURN
P0300 2002 FORD EXPEDITION
P0300 MERCURY
P0300 HUMMER
P0300 OLDSMOBILE