One problem related to engine knocking noise has been reported for the 2002 GMC Sierra. The most recently reported issues are listed below.
GMC serria 2002. Our truck has rust on the bumper behind the painted cover. The dealer suggested this is normal and polished it, within one week the bumper showed rust again. The driver's side door is not lined up correctly, the dealer tried to adjust it, the result is the door must be slammed to close it. The motor makes knocking sounds at the start as if it has no oil. The oil has been changed every three thousand miles. The knock started after the truck turned four thousand miles. The dealer told us that gm reports the knock is normal. It is the first time iã‚ve heard of a gas motor having an intentional knock. We have had the truck this since it was new and have had the dealer do all the regular maintenance including tire rotations and oil changes.