Visual Inspection

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure harness connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. If necessary, see appropriate VACUUM DIAGRAMS article to verify routing and connections. Inspect air induction system for possible vacuum leaks or restrictions. Check for air leaks at all intake manifold sealing surfaces. Check ignition wires for cracking, hardness, proper routing and carbon tracking. Ensure PCM and MIL are functioning properly. Ensure there are no DTCs stored, or only intermittent DTCs are present.

After all checks have been performed, verify customer complaint and locate correct symptom. Check items indicated under that symptom. These procedures will normally recommend testing of a specific system or component, such as EGR, ignition, TCC, etc. Go to SYSTEM & COMPONENT TESTING - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article for appropriate test procedures.