Symptom Checks

Check the following items:

• Check cooling system for overheating. If cooling system is overheating, go to ENGINE RUNS HOT symptom.
• Check ignition timing. See ADJUSTMENTS article.
• Check EGR system. See SYSTEM/COMPONENT TESTS article.
• Check ignition system. See CIRCUIT TEST JD in TESTS W/CODES article.
• Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
• Check octane adjust system. See CIRCUIT TEST FG in TESTS W/CODES article. If available, check Technical Service Bulletins (TSBs) for OCT ADJ information.