Symptom Checks

Check the following items:

• Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
• Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
• Check fuel pump. See FUEL SYSTEM in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
• Check PCV system.
• Ensure engine operates at normal operating temperature.
• Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
• Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check air intake system. Also, ensure throttle plate and linkages operate properly.
• Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check charging system.
• Check exhaust system.
• On 3.0L SHO and 3.2L SHO, check Intake Manifold Runner Control (IMRC). See step 6) in CIRCUIT TEST KT under G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.