Does your 2006 or newer GM vehicle have a knocking or ticking sound coming from the engine, usually accompanied by a rough idle and/or shaking and lack of power? Another symptom is excessive oil consuption, with no visible leak.
This may be the result of a faulty AFM (Active Fuel Management for displacement-on-demand) lifter that unlocks as soon as the engine is started or one that is mechanically collapsed/stuck. This is a fairly common issue in General Motors Active Fuel Management vehicles, and is often misdiagnosed as a bottom end knock, a bent or worn pushrod, worn or damaged valvetrain
This applies to the following vehicles:
- 2008-2009 Buick LaCrosse, Allure (Canada only)
- 2007-2009 Cadillac Escalade
- 2007-2009 Chevrolet Avalanche
- 2007-2009 Chevrolet Silverado, Suburban, Tahoe
- 2006-2009 Chevrolet Trailblazer
- 2006-2009 Chevrolet Impala SS
- 2006-2007 Chevrolet Monte Carlo SS
- 2006-2009 GMC Envoy
- 2007-2009 GMC Sierra, Yukon
- 2005-2008 Pontiac Grand Prix GXP
- 2006-2009 Saab 97x
- (with a V8 engine and AFM (RPO Codes L76, LC9, LFA, LH6, LMG, LS4 and LYS)
There are two ways in which these lifters fail. They either lock in the extended position, preventing the Active Fuel Management system from functioning properly, causing the engine to run erratically and causing the “Check Engine” light to come on, or the lifters collapse and cause cylinders to be deactivated completely which results in misfires, excessive oil consumption, and a ticking or knocking sound. Either way these faulty lifters need to be replaced as soon as possible in order to prevent further damage to your engine.
Here at Integrity AutoWorks we have repaired this issue on many GM cars and trucks and we do them quicker and less costly than just about anyone. Give us a call today and let us give you a quote and set up an appointment to get your vehicle back in top shape today!