GM Service Manual Online
For 1990-2009 cars only

Engine Noise - keywords booster brake cable cover engine knock noise shift spark steady transmission vibrate

Subject:Engine Noise

Models:2006-2007 Buick Lucerne
equipped with a 3800 engine



This PI was superseded to update Condition/Concern and Recommendation/Instructions. Please discard PIP4123A.


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

Condition/Concern:

Some owners may comment about a noise coming from the engine when accelerating or when at steady speeds. Some may comment that the noise sounds like spark knock.

The engine cover may be contacting or vibrating against the transmission shift cable. In addition the shift cable may be contacting the side of the brake booster down behind the engine.

Recommendation/Instructions:

If the engine cover is contacting the cable then remove the cover and using plastic tie straps, attach a small piece of closed cell foam material to the cable at the point(s) where contact is taking place with the engine cover. Use a plastic tie strap to secure the shift cable away from the brake booster.


Object Number: 1964818  Size: SH

Object Number: 1964819  Size: SH

If the customers complaint was that the engine has spark knock, detonation or is "knocking" during acceleration, please contact James B. Kelly @586-492-5612 and supply him with the VIN and mileage from the vehicle. Also advise him whether insulating the cable from the engine cover reduced or eliminated the noise.

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.