Low Power Poor Performance Or Busy Shifting - keywords 6.2 6L80 L80 L92 6sp accel accelerate apply APP clunk coast delay delayed down downshift engine fuel hesitate hesitation 180 late lazy MYC shift
| Subject: | Low Power, Poor Performance, or Busy Shifting |
| Models: | 2007-2008 Cadillac Escalade |
| 2007-2008 GMC Sierra Denali, Yukon Denali |
| 2008 Hummer H2 |
| Equipped with the 6.2L Engine (RPO code L92) and a 6L80 Automatic Transmission (RPO code MYC) |
This PI was superseded to update models. Please discard PIP4168.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may have a concern of low power, busy shifting, delayed transmission downshifts, or poor performance.
The customer may also explain they have to depress the throttle pedal farther than expected to get the acceleration desired.
These conditions may be caused by the use of regular grade fuel instead of the recommended premium grade fuel with a posted octane of 91 or higher. When regular grade fuel is used, the engine will produce less power, and the transmission shifting characteristics will change.
Recommendation/Instructions:
When evaluating any of these driveability concerns it is important to determine if the vehicle is being operated on regular grade fuel. The owner's manual recommends the use premium unleaded gasoline with a posted octane rating of 91 or higher.
If the vehicle is being operated on regular grade fuel, request that the customer use at least two tanks of premium fuel with an octane rating of 91 or higher before returning for evaluation of the driveability concern.
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.
