Preliminary Inspection

• Verify on-vehicle diagnostics are working by performing DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.2L CTS article.
• Ensure ECM grounds are clean, tight, and properly located.
• Check vacuum hoses for splits, kinks, leaks, restrictions and proper connections. Ensure vacuum hoses are correctly routed as shown on Vehicle Emission Control Information (VECI) label.
• Check for air leaks at all intake manifold sealing surfaces.
• Check ignition wires for cracking, hardness, proper routing and carbon tracking.
• Check wiring for proper connections and routing, pinches, burns, cuts or other damage.
• Ensure ECM and MIL are functioning properly.
• Ensure there are no DTCs stored, or only intermittent DTCs are present.
• Ensure fuel control system is operating properly. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES- 3.2L CTS article.
• Perform a careful visual inspection of all systems.

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. See SYSTEM & COMPONENT TESTING - 3.2L CTS article for specific system or component test procedures.