Possible Cause & Correction

Check the following items:

• Check for obvious overheating problems.
• Check TP sensor adjustment and operation.
• Check fuel pressure.
• Check knock sensor system for no retard.
• Check EGR system (not opening).
• Check TCC system operation (applying too soon).
• Remove carbon from engine with top engine cleaner.
• If excessive carbon exists in combustion chamber, check for excessive oil burning due to leaking valve guide seals.
• Check for incorrect basic engine parts such as camshaft, cylinder heads and pistons.
• Ensure the installed PROM and/or PCM is correct for the particular vehicle. Check with dealer for latest application information.
• Check engine coolant sensor for shift in calibration. See appropriate SENSOR OPERATING RANGE CHARTS article.
• Check for rich or lean running conditions.
• Check spark plugs for proper application and heat range.
• Check engine compression.
• Check Transaxle Range (TR) switch. Ensure scan tool indicates proper gear range as selected.
• Check distributor vent system (if equipped).
• Check for contaminated or poor quality fuel.
• Check vehicle operation using a higher octane fuel.