DTC P0300: Random Misfire Detected, Or P0301-P0304 Cylinders No. 1-4 Misfire Detected: Condition

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor input signal interval time. It detects a misfire in a specific cylinder by calculating change of CKP interval time for each cylinder. While engine is operating, PCM counts number of misfires that occurred during 200 crankshaft revolutions and during 1000 crankshaft revolutions in order to calculate a misfire ratio for each crankshaft revolution. If misfire ratio exceeds a preprogrammed criteria during 200 crankshaft revolutions, PCM determines that a misfire has occurred which can damage the catalytic converter, will set a DTC and will flash MIL. If misfire ratio exceeds a preprogrammed criteria during 1000 crankshaft revolutions, PCM will set a DTC and illuminate MIL when it detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Engine overheating.
• Intake system vacuum leaks.
• Secondary ignition system malfunction.
• Incorrect fuel pressure.
• Plugged or leaking fuel injector.
• Incorrect engine compression.
• Incorrect valve clearance.
• Manifold Absolute Pressure (MAP) sensor malfunction.
• Engine Coolant Temperature (ECT) sensor malfunction.
• PCV valve malfunction.
• EVAP control system malfunction.
• EGR system malfunction.