One problem related to engine funny noise has been reported for the 2002 GMC Sierra. The most recently reported issues are listed below.
On cold starts the engine produces loud rapping sound as if running on no oil. GMC has been notified, but it is deemed a normal operating sound, and will not shorten the engine life. They never made any attempt to fix problem, just offered an extended warranty on certain parts. It really makes me wonder how they know what parts to cover on the extended warranty if there is nothing wrong with the engine? dt.