P0300 KIA - Random/Multiple Cylinder Misfire Detected
Possible causes
- 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
Tech notes
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 persists more tests needs to be done to diagnose problem, see "Possible Causes"
There is a factory service bulletin for the following KIA models:
Rio (JB)
Soul (AM)
Optima (MG)
Rondo (UN)
Forte (TD)
Spectra (LD)
Sportage (KM)
Optima (MG)
Sedona (VQ)
Amanti (GH)
Borrego (HM)
Sedona (VQ)
Sorento (BL)
Borrego (HM)
The bulletin provides information on how to inspect and diagnose problems related to the Oil Control Valve (OCV) used in Constant Variable Valve Timing (CVVT), if at any time the OCV is suspected as the caused of rough idling, poor acceleration, camshaft timing misalignment-related trouble codes, misfire-related trouble codes.
Bulletin: Kia Constant Variable Valve Timing Oil Control Valve Inspection
There is a factory service bulletin for the following KIA models:
Rio (JB)
Soul (AM)
Optima (MG)
Rondo (UN)
Forte (TD)
Spectra (LD)
Sportage (KM)
Optima (MG)
Sedona (VQ)
Amanti (GH)
Borrego (HM)
Sedona (VQ)
Sorento (BL)
Borrego (HM)
The bulletin provides information on how to inspect and diagnose problems related to the Oil Control Valve (OCV) used in Constant Variable Valve Timing (CVVT), if at any time the OCV is suspected as the caused of rough idling, poor acceleration, camshaft timing misalignment-related trouble codes, misfire-related trouble codes.
Bulletin: Kia Constant Variable Valve Timing Oil Control Valve Inspection
When is the code detected?
The control module monitors the crankshaft speed and has detected a misfire condition
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/loss of power
- Hard start
- Engine hesitation
P0300 KIA Description

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