- Important Preliminary Checks

Before using Symptoms, perform the Powertrain On-Board Diagnostic System Check and verify all of the following items: Testing and Inspection

^ The PCM and Malfunction Indicator Lamp (MIL) (Service Engine Soon) are operating correctly.
^ There are no DTC(s) stored.
^ Ensure that the engine coolant temperature is not above 130°C (266°F). This condition will cause the PCM to operate in Engine Metal Overtemp. While in Engine Metal Overtemp, the PCM will turn fuel off to four cylinders at a time to keep engine temperatures from reaching damaging levels. Engine Metal Overtemp will be perceived as a lack of power, miss, or rough idle. If the vehicle is operating in Engine Metal Overtemp, refer to Cooling System for diagnosis.
^ Scan tool data is within normal operating range. Refer to Typical Scan Data Values. Scan Tool Testing and Procedures
^ Verify the customer complaint and locate the correct symptom in the table of contents. Perform the procedure included in the symptom chart.