Before Starting

Before using this section you should have performed the DIAGNOSTIC CIRCUIT CHECK and found out that:

1. The ECM and "SERVICE ENGINE SOON" light are operating.
2. There are no trouble codes stored, or there is a trouble code but no "SERVICE ENGINE SOON" light.
3. The fuel control system is operating OK (by performing Field Service Mode Check).

Verify the customer complaint, and locate the correct SYMPTOM below. Check the items indicated under that symptom.

If the ENGINE CRANKS BUT WILL NOT RUN, see CHART A-3.
Several of the symptom procedures below call for a Careful Visual Check. This check should include:
^ ECM grounds for being clean and tight
^ Vacuum hoses for splits, kinks, and proper connections, as shown on Emission Control Information label.
^ Air leaks at throttle body mounting and intake manifold.
^ Air leaks between MAF sensor and throttle body.
^ Ignition wires for cracking, hardness, proper routing, and carbon tracking.
^ Wiring for proper connections, pinches, and cuts. The importance of this step cannot be stressed too strongly - it can lead to correcting a problem without further checks and can save valuable time.