Possible Cause & Correction
Check the following items:
- Visually check vacuum hoses for splits, kinks and proper connections as shown on vehicle emission control information label.
- Check canister purge system for proper operation.
- Check ignition control system for proper operation.
- Check EGR system for proper operation.
- Ensure the installed PCM program is correct for that particular vehicle. Check with dealer for latest application information.
- Check for proper ignition voltage output using Spark Tester (J-26792).
- Check Heated Oxygen Sensor (HO2S) for contamination. This will cause a false high voltage signal to PCM. PCM will respond by leaning out air/fuel ratio.
- Check in-line fuel filter, and replace if dirty or clogged.
- Check fuel pressure while condition exists. See FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
- Check for poor quality or alcohol contaminated fuel.
- Check Mass Airflow (MAF) sensor for proper operation. Check air induction system for damage, restriction or air leaks. See DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
- Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits. Also, check condition of spark plug wires. Spray spark plug wires with a fine mist of water to check for shorts.
- Check charging system output. Repair charging system if voltage is less than 9 volts or more than 16 volts.
- Check for restricted exhaust system, such as a damaged or collapsed pipe, muffler or catalytic converter.
- Check transmission shift solenoid system and Torque Converter Clutch (TCC) system for proper operation.
- Ensure owner understands operation of TCC and A/C clutch operation, as stated in owners manual.
- Check injector harness locations. Ensure injectors are connected to correct injector/cylinder according to firing order.
- Check for rich or lean conditions. Drive vehicle at speed when complaint occurs. See appropriate HO2S DTCs for diagnostic aids. See appropriate SELF-DIAGNOSTICS article.
- Check for plugged injectors. Perform injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
- Ensure PCM grounds are clean and tight.
- Check for excessive use of additives in fuel.
- Ensure that the engine coolant temperature is not above 266°F (130°C). This condition causes the PCM to operate in Engine Coolant Over Temperature-Fuel Disabled Mode. While in Engine Coolant Over Temperature-Fuel Disabled Mode, the PCM turns fuel OFF to 4 cylinders at a time in order to keep engine temperatures from reaching damaging levels. The system perceives Engine Coolant Over Temperature-Fuel Disabled Mode as a lack of power, a miss, or a rough idle.