Three problems related to diesel engine have been reported for the 2004 GMC Sierra. The most recently reported issues are listed below.
2004 Sierra caught on fire due to a malfunction in the truck.
The injectors on my 2004 GMC Sierra went out at 26,000 miles. The incident caused me to lose my truck for 4 days. The dealership replaced all 8 injectors.
2004 GMC 2500hd duramax - purchased March 2004. Severe, abrupt 'clacking/chatter' coupled with brief, complete loss of power and billows of smoke. Has occurred 4 times: 3/28 1660 miles @ 67mph, 5/5 2167 miles @ 70 mph, 5/8 2316 miles @ 60-65 mph, 5/8 2325 miles @ 60-65 mph.