[derekbitt]

from what i know this is a common problem, you will read many compliants about these motors. Chevy does have a program about these motors but they dont advertise it or offer it, you will really have to go after them to get them to do something about it.. if you take it to the dealer they will tell you that nothing is wrong with the engine and the knock will not cause any problems. the word is that combustion chamber gets carbon deposits and these deposits soften as the engine warms and the knockn quits. I have read that chevy bought some vehicles back from customers but not after a huge fight from the customer. if you have the 100k warranty you better get after this befor it expires. Good Luck. just remember your 40,000$ truck should make these noises when the dealer tells you nothing is wrong. I love chevy trucks but this crap is why i bought my wife a Toyota sequoia. sorry to be so negative.