- Preliminary Information

This section is used to find the correct test procedure for a given symptom. The symptoms and actions in this section are Emission related only. For Computerized Engine Controls Diagnosis By Symptom, refer to the "COMPUTERIZED ENGINE CONTROLS" section. Always use the Flow of Diagnosis for proper testing sequence. Verify the correct system application to ensure that the vehicle has the given component(s).

Before proceding to the appropriate symptom perform the following inspection:

NOTE: It is essential that the vehicle has been properly warmed up and is at operating temperature (except when attempting to diagnosis a cold driveability problem). The catalytic converter and feedback systems will not function as designed if this is not achieved. Failure to do so will result in inaccurate test results.

VISUALLY CHECK:

1 Vacuum hoses for splits, kinks, and proper routing.
2 Ignition wires for cracking, hardness, and proper connections at both the distributor and spark plugs.
3 All wiring for proper connections, pinches, and cuts.
4 Harnesses for proper routing.