I have a 2008 Chevrolet Silverado 5.3 crew cab 4x4 with 80000 miles on it.Changed oil every 4000 miles have always used 5w 30 synthetic pennzoil.Stabile track and stabile traction,and engine light come on cruising down the road and this happens knocking noise and missing.Pull over and have a p306 code ,cylinder 6 misfire.Have replaced plugs,wires,coils and also replaced injectors.Fixing to tear motor down to see if it's a lifter or a camshaft.Im just about through with gym and these crap motors.GM should be ashamed for selling these engines when they want stand behind them.Truck body is in immaculate shape but engine is no good.My question is why don't gym stand behind there product!!!

 

So this mourning I called GM headquarters to complain about my 2008 Silverado 5.3 4x4 crew cab.Cylinder 6 misfire and with knocking.This vehicle has 80323 miles has always been maintained and in immaculate condition.Oil changes every 4500 miles and have used 5w-30 synthetic oil.After they gave me a case number I was told that I need to take my truck to a dealership to have a diagnostic run on my vehicle.My mechanic has same programs in his computer and gets updates that he pays for on an annual basis from GM.I have turn my motor down and the problem is the plastic lifter retainer.Lifter will spin around.Cam shaft will have to be replaced along with all lifters.GM needs to stand by there products!!! It seems that all they are concerned about is profit.After talking to several GM mechanics this is a big problem.AFM and cheap products are not good!

 

Davey,

If GM is going to assist you with an after warranty adjustment (AWA), it would have to happen through a dealership which is why they told you you have to take it back to a dealership. If you bought it new and have serviced it via that dealership you might have a chance if it's a know issue. If you bought it used and serviced at an indie repair shop I'd say your chances are pretty slim.