- Important Preliminary Checks

BEFORE STARTING
Before using this section you should have performed the "On-Board Diagnostic (OBD) System Check" and determined that:

1. The PCM and MIL (Service Engine Soon) are operating correctly.
2. There are no diagnostic trouble codes stored, or if there is a diagnostic trouble code but no MIL (Service Engine Soon).
3. Tech 1 typical scan data is within normal operating range as listed in Scan-Tool Diagnostics. Testing and Inspection

SYMPTOM
Verify the customer complaint, and locate the correct symptom in the table of contents. Check the items indicated under that symptom.

VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful visual/physical check. 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. This check should include:
- PCM grounds for being clean, tight and in their proper location.
- Vacuum hoses for splits, kinks, and proper connections, as shown on "Vehicle Emission Control Information" label. Check thoroughly for any type of leak or restriction.
- Air leaks at throttle body mounting area and intake manifold sealing surfaces.
- Ignition wires for cracking, hardness, proper routing and carbon tracking.
- Wiring for proper connections, pinches and cuts.