PCM Calibration Update - VIN S 4.2L Engine - Rough Idle During Low Speed Deceleration - kw LL8 intermittent no park surge turn

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

Some 2004 models equipped with the 4.2L (VIN S - RPO LL8) may experience a rough idle during low speed deceleration, such as parking lot maneuvers.

.

If the SI diagnostics does not isolate a concern, reprogram the PCM with the latest TIS2000 calibrations. An updated PCM engine calibration has been released to address this issue. In TIS2000, this updated calibration is titled "Calibration to address coast down idle roughness and revise cruise control operation with less vehicle speed deviation. Also contains diagnostic enhancements for DTC P0171". This calibration or any that follow are designed to address the above concerns.

.

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.

(04 Buick Rainier with the 4.2L Engine) and (04 Chevrolet Trailblazer with the 4.2L Engine) and (04 GMC Envoy with the 4.2L Engine) and (04 Oldsmobile Bravada with the 4.2L Engine)

.