Engine Noise Rough Idle Poor Performance SES Light Illuminated And DTC P0300 - keywords chuggle DTC idle L26 MIL misfire noise P0300 PCM rough SES surge
| Subject: | Engine Noise, Rough Idle, Poor Performance, SES Light Illuminated and DTC P0300 |
| Models: | 2008 Pontiac Grand Prix |
| 2008 Buick Lucerne, LaCrosse, Allure |
| Equipped with 3800 Engine RPO Code L26 (VIN 2) |
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 is making noise, idles rough and/or has poor performance. Others may comment that the SES light is illuminated. Upon inspection you may find DTC P0300 is stored in the Powertrain Control Module (PCM).
Recommendation/Instructions:
An intake or exhaust valve spring may have broken.
Replace the broken valve spring with a new spring. Also inspect the spring cap, valve stem, both locks and other components for damage and replace if necessary. Then contact Jim Kelly on (586) 492-5612 and he will supply you with a parts waiver and shipping information on where to send the broken spring (including pieces).
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.
