Symptom Checks

Check the following items:

• Perform QUICK TEST. See the TESTS W/CODES - EEC-IV article. If code is present, use appropriate CIRCUIT TEST.
• Check ignition system. See IGNITION SYSTEMS in the SYSTEM/COMPONENT TESTS article.
• Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in the TESTS W/CODES - EEC-IV article.
• Check idle speed. See IDLE SPEED in the ADJUSTMENTS article.
• Check PCV system.
• Check Evaporative Emission (EVAP) system. See the SYSTEM/COMPONENT TESTS article.
• Check secondary air injection. See the SYSTEM/COMPONENT TESTS article.
• Check for restricted exhaust system.
• Check EGR system. See the SYSTEM/COMPONENT TESTS article.
• Check Intake Manifold Runner Control (IMRC). See step 6) of CIRCUIT TEST KT in the TESTS W/CODES - EEC-IV article.
• Ensure engine operates at normal operating temperature.
• Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
• Check base ignition timing (if not already checked).