GM Service Manual Online
For 1990-2009 cars only

Several of the symptom procedures call for a careful Visual/Physical. check. It can lead to correcting a problem without further checks and can save valuable time. This check should include the following items:

    •  Check PCM grounds for being clean, tight, and in their proper location.
    •  Check vacuum hoses for splits, kinks, and proper connections, as shown on Vehicle Emission Control Information label -- Check thoroughly for any type of restriction.
    •  Check air intake ducts for collapsed or damaged areas.
    •  Check air leaks at throttle body mounting area, Mass Air Flow (MAF) sensor and intake manifold sealing surfaces.
    •  Check ignition wires for cracking, hardness, proper routing and carbon tracking.
    •  Check wiring for proper connections, pinches and cuts.