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 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 ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check for restricted exhaust system.
• Ensure engine operates at normal operating temperature.
• Check air intake system. Also, ensure throttle plate and linkages operate properly.
• On 3.0L SHO and 3.2L SHO, 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.
• Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
• Ensure transmission is functioning properly.
• On 3.8L SC, ensure supercharger operates properly. See AIR INDUCTION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check for binding/dragging brakes.
• Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Ensure A/C turns off during Wide Open Throttle (WOT). On all models except Mark VIII, if A/C does not turn off during WOT, go to CLIMATE CONTROL (LACK OF COOLING) symptom.
• On Mark VIII, check high speed fuel pump operation. See step of CIRCUIT TEST XB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.