Diagnosis By Symptom Test

Use this test procedure only when directed to do so by results of QUICK TEST  or steps in CIRCUIT TESTS  . Follow test procedures carefully.

1. When engine stalls in operation or during SELF-TEST, runs rough or misses, has an "always rich" or "always lean" condition, perform the following checks:
   • Perform SYSTEM CHECK, ISC Check. Use CIRCUIT TEST SS  , step 1).
   • Check BP sensor, using CIRCUIT TEST H  , step 11).
   • Check Idle Speed Control (ISC), using CIRCUIT TEST Z  , step 1).
   • Check for, and repair, any bad ground or power connections.
   • Check ignition components (cap, rotor, wires, coil and plugs).
   • Check for short to ground, using CIRCUIT TEST V  , step 9).
   • Check basic engine components (valves, cam timing, compression, etc.).
2. When detonation (spark knock) occurs, go to CIRCUIT TEST I  , step 1).
3. If on restarts, high idle speeds and 3-5 minutes of detonation occur, go to CIRCUIT TEST I  , step 1).
4. If no fast idle occurs when A/C is turned on, go to CIRCUIT TEST M  , step 1).
5. If gasoline fumes accumulate in engine compartment, go to CIRCUIT TEST Y  , step 1).
6. If shift indicator light is always on or off, go to CIRCUIT TEST FF  , step 1).
7. If A/C does not cut-off under wide open throttle (WOT) conditions, go to CIRCUIT TEST GG  , step 1).
8. If vehicle is sluggish or if performance is poor, boost control is not working correctly. Go to CIRCUIT TEST HH  , step 1). Also perform this test if detonation (engine knock) occurs.