My 2004 3500 Duramax loses power while pulling a 35 foot 5th wheel and speed drops to about 40 mph fuel consumtion goes up and engine runs real rough. I stopped and checked trailer brakes and then it ran OK. Also if I shut the engine off for a few minutes, it runs OK. It only deoes this once or twice a day. GMC said it was fuel filter and replaced it, didn't help. They checked computer and it showed no problems. No warning lights come on I'm afraid it is going to leave me stranded one of these days. What do I need to do?
My 2004 3500 Duramax loses power while pulling a 35 foot 5th wheel and speed dro on 2004 GMC Sierra 3500
by timberlake in Golden, CO on May 21, 2012
ANSWER by diver-don on September 01, 2013
I had a similar problem with my 2005 GMC 3500. I replaced the fuel filter about 4 times in 1 month before coming to the conclusion it wasn't that and it wasn't the fuel injectors that the mechanics were telling was the problem. Everytime I changed the fuel filter, I also pumped up the pressure (bleeding air out of the fuel filter) as is normal when changing the fuel filter. The last time I lost power, I pulled over to the side of the road, turned the engine off, then simply pumped up the fuel filter pressure.... Presto... full power once again.... Over the last 3 years, I will still lose power once in awhile, but only when I really push the truck. Hope this helps.