| Subject: | Rough Engine Idle, Misfire (DTC P0300) or Noise from Engine Compartment |
| Models: | 2008 Chevrolet Impala, Malibu, Uplander |
| Equipped with 3.5L or 3.9L Engine (RPO Code LZE, LZ4, LGD, LZ9, LZG) VIN Code K, N, W, 1, 3 |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment that the engine appears to have a rough idle or is misfiring, while others may say that they hear a noise coming from the engine compartment.
Recommendation/Instructions:
Verify which cylinder the misfire or noise is coming from. Once the cylinder has been identified, and you have verified that the fuel delivery system and ignition system is not the cause, then remove the rocker cover from the appropriate cylinder head.
With the rocker cover removed, inspect for a loose rocker arm. If a loose rocker arm is found, remove it and inspect the push rod for a missing "ball" or "tip". If you find that a pushrod has a missing "ball" or "tip", then contact Jim Kelly at (586) 492-5612.
He will supply you with proper repair information, a parts waiver, and information on where to send the push rod to.
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.
