Possible Causes

These DTCs use two-trip detection logic. DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are:

• Open or short in engine wiring harness.
• Defective connections at ECM or component.
• Disconnected, restricted or damaged vacuum hose(s).
• Defective vacuum hoses or connections.
• Ignition system malfunction.
• Defective fuel injector(s).
• Improper fuel pressure.
• Defective Mass Airflow (MAF) meter.
• Defective Engine Coolant Temperature (ECT) sensor.
• Improper engine compression.
• Improper valve clearance.
• Improper valve timing.
• Defective ECM.

If misfire cannot be reproduced, reason may be because of driving with lack of fuel, improper fuel, fouled spark plug, etc.