Symptom Checks

Perform the following:

• Check cooling system for overheating. If cooling system is overheating, go to ENGINE RUNS HOT (OVERHEATING) symptom.
• Check base timing. See step  5 of DIAGNOSTIC SUB-ROUTINES.
• Perform Key On Engine Off (KOEO) Self-Test. See step  1 of DIAGNOSTIC SUB-ROUTINES.
• Check engine mechanical condition. Check compression, intake manifold gasket, camshaft, valve train components, etc.
• Check fuel delivery system. See FUEL SYSTEM in appropriate I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check Exhaust Gas Recirculation (EGR) system. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check Positive Crankcase Ventilation (PCV) system. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check air injection. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Ensure transmission is functioning properly.
• Check engine oil quality.