Symptom Checks

Check the following items:

• Check the following Parameter Identification (PID) values: DPFEGR, ECT, IAC, LONGFT 1, LONGFT 2, VPWR and VREF. See appropriate article:

  For 2.5L vehicles, see PIN VOLTAGE CHARTS - 2.5L .

  For 3.0L & 4.0L vehicles, see PIN VOLTAGE CHARTS - 3.0L & 4.0L .

  On some vehicles, all PIDs may not be applicable.

• Check fuel delivery system. See CIRCUIT TEST HC in appropriate article:

  For 2.5L vehicles, see TESTS W/CODES - 2.5L .

  For 3.0L vehicles, see TESTS W/CODES - 3.0L .

  For 4.0L vehicles, see TESTS W/CODES - 4.0L .

• Check secondary ignition system. See CIRCUIT TEST JB in appropriate TESTS W/CODES article.
• Check exhaust system. See CIRCUIT TEST HF in appropriate article:

  For 2.5L vehicles, see TESTS W/CODES - 2.5L .

  For 3.0L vehicles, see TESTS W/CODES - 3.0L .

  For 4.0L vehicles, see TESTS W/CODES - 4.0L .

• Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
• On A/T vehicles, ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. See TRANSMISSION SERVICE & REPAIR article.
• Check for binding/dragging brakes.
• On M/T vehicles, check clutch operation. On all vehicles, check charging system. Check customer driving habits (i.e., driving with excessive loads). If no problems are indicated, return to SYMPTOM DIAGNOSIS  to identify any additional symptoms or go to CIRCUIT TEST Z in appropriate article and check for intermittent faults:

  For 2.5L vehicles, see TESTS W/CODES - 2.5L .

  For 3.0L vehicles, see TESTS W/CODES - 3.0L .

  For 4.0L vehicles, see TESTS W/CODES - 4.0L .