Symptom Checks

Perform the following:

• Check RPM drop using step 2) of CIRCUIT TEST S, or power to MAP/BARO sensor using step 3) of CIRCUIT TEST S. Proceed to TESTS W/CODES - EEC-IV article in the ENGINE PERFORMANCE section.
• Check ignition system. Proceed to IGNITION SYSTEMS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE section.
• Check fuel delivery and fuel pump. See FUEL SYSTEM in TESTS W/CODES - EEC-IV article in the ENGINE PERFORMANCE section.
• Check Positive Crankcase Ventilation (PCV) system. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• Ensure engine operates at normal operating temperature.
• Check Exhaust Gas Recirculation (EGR) system. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• Check engine mechanical condition. Check compression, camshaft, valve train components, intake manifold gaskets, etc.
• Check air injection. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• Check air intake system. Ensure throttle plate and linkages operate properly.
• Check Fuel Evaporation (EVAP) system. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
• Check for restricted exhaust system.