For 1990-2009 cars

#### Before Starting

Before using this section, you should have performed the Powertrain On-Board Diagnostic (OBD) System Check and determined the following results:

• | The PCM and the MIL (Check Engine) are operating correctly.

• | There are no DTC(s) stored.

• | The scan tool data is within the normal operating range. Refer to the Engine Scan Tool Data List.

Verify the customer complaint and locate the correct symptom in the table of contents. Check the items that are 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 strongly enough. This step can lead to correcting a problem without further checks and can save valuable time. This check should include the following conditions:

• | The PCM grounds for being clean, tight, and in the proper location.

• | The vacuum hoses for splits, kinks, and proper connections, as shown on the Vehicle Emission Control Information label. Check the hoses thoroughly for any type of leak or restriction.

• | Air leaks at the throttle body mounting area and the intake manifold sealing surfaces

The wiring for proper connections, pinches and cuts