- Faulty spark plug 1
- Clogged or faulty fuel injector 1
- Faulty ignition coil 1
- Fuel injector 1 harness is open or shorted
- Fuel injector 1 circuit poor electrical connection
- Ignition coil 1 harness is open or shorted
- Ignition coil 1 circuit poor electrical connection
- Insufficient cylinder 1 compression
- Incorrect fuel pressure
- Intake air leak

The P0301 code means that the cylinder 1 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 1. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"

Engine Cylinder 1 is misfiring.

- 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.

P0301 BMW
P0301 CHRYSLER
P0301 JEEP
P0301 DODGE
P0301 HONDA
P0301 ACURA
P0301 HYUNDAI
P0301 INFINITI
P0301 NISSAN
P0301 ISUZU
P0301 KIA
P0301 LEXUS
P0301 TOYOTA
P0301 SCION
P0301 MAZDA
P0301 MITSUBISHI
P0301 SUBARU
P0301 AUDI
P0301 VOLKSWAGEN
P0301 GMC
P0301 CHEVROLET
P0301 PONTIAC
P0301 FORD
P0301 BUICK
P0301 CADILLAC
P0301 MERCURY
P0301 VOLVO
P0301 HUMMER
P0301 JAGUAR
P0301 SATURN