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 power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
• Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
• Check PCV system.
• Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check for restricted exhaust system.
• Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• On Mark VIII, check Intake Manifold Runner Control (IMRC). See step 6) of CIRCUIT TEST KT in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
• Ensure engine operates at normal operating temperature.
• Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
• Check PCV system.