Possible Cause & Correction

Check the following items:

• Check TP sensor adjustment and operation.
• Check fuel system. Perform BASIC FUEL SYSTEM CHECKS. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
• Check fuel injectors. Perform injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
• Check Knock Sensor (KS) system for no retard.
• Check EGR system (insufficient).
• Check Torque Converter Clutch (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 PCM program is correct for the particular vehicle. Check with dealer for latest application information.
• Check for low engine coolant.
• Check cooling fan for proper operation.
• Check for restricted airflow to radiator or restricted coolant flow through radiator.
• Check for loose water pump belt.
• Check engine coolant sensor for shift in calibration. See appropriate SENSOR OPERATING RANGE CHARTS article.
• Check for rich or lean running conditions.
• Using Spark Tester (J-26792), check available output voltage of ignition coil.
• Check for crossfire between spark plugs and spark plug wires. Check for shorts and faulty insulation by spraying spark plug wires with a fine water mist.
• 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 for alcohol contaminated or poor quality fuel.
• Check vehicle operation using a higher octane fuel (minimum 87 octane).