Rough Running On Initial Cold Start - Reprogram PCM - keywords 07030 all calibrate calibration cylinders DTC engine foul fouled fouling hesitate idle intermittent light LLV MIL misfire miss no on

This PI was superseded to update the Recommendation/Instructions. Please discard PIP4047.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

On rare occasions, a brief rough running concern may experienced for up to 2 minutes after cold starting the engine. After start up, the concern will not occur again until the vehicle sits with the engine off for a few hours. Typically, no DTCs will be stored but a P0300 and random misfires on all cylinders may occur if the concern lasts long enough. This may be the result of a PCM calibration concern.

If the SI diagnostics do not isolate a cause for this concern, reprogram the PCM with the latest TIS2Web calibrations, which are currently titled "new calibration to correct rough idle after cold start". These calibrations, or any that follow, are designed to improve this concern.

In some instances, the updated calibrations above may not eliminate this concern 100%. As a result, some vehicles may continue to exhibit this concern for approximately 5 seconds but the P0300 should no longer set since the rough running concern should no longer last long enough to set a P0300 once the updated PCM calibrations are installed. If the SI diagnostics do not isolate a cause for this concern that lasts approximately 5 seconds once the updated PCM calibrations are installed, test the fuel injectors with the AFIT as outlined in 03-06-04-030E and repair as necessary. If there is no problem found, no DTCs stored, and the concern only lasts approximately 5 seconds, it should be considered a characteristic of the updated calibration.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.