04 Chevrolet Colorado/ GMC Canyon w/ 3.5L L52 Vibration at Idle or Rough Idle - kw engine exhaust 3.5 GMT355 motor noise rattle

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Vibration at idle and/or rough idle.

This may be caused by the idle RPM being too low. Please follow the vibration and rough idle diagnostics in SI. If no other vehicle component issue is identified, please reprogram the PCM with the latest software available in TIS version 7.4 released July 21, 2004. The calibration is titled "new calibration to improve idle quality" and can be found by clicking on the engine tab in TIS2000. Please note this only applies to the Extended and Crew cab models as the increase in RPM tends to make the issue worse on standard models.

.

Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(04 Chevrolet Colorado) and (04 GMC Canyon)

.