I have an 03 Duramax with 75K. Lost power around 65K but still ran smooth withoout a load. Finally got it into the dealer and they said injectors. Covered under warrenty but still charged me a deductable of $100.00. Truck runs much better now but still seems slightly down from new. Another thing to check is the air filter. Fram makes a replacement filter that will collaps and choke the engine causing a loss of power. Your air filter should have at least three lines of glue on the inlet side. This keeps the filter element from folding over and choking the engine. Check all the simple things first (fuel filter) but sure sounds like injectors to me. I was told that the injectors can pass too much gas back the tank also causing low fuel rail pressure. Also watch your oil level. If it raises, thats a sign that the injectors are leaking and the fuel is going into the oil. 2004 and newwer this is supposed to be corrected so that if they leak, it does not go into the oil.

Good Luck!

Any other questions, PM me and I'll gladly share what I know. I just went thru the bad injector thing.

I dropped it off at the dealer this morning. They said it sounded like the injectors also. Yep $100 deductable.

About a year ago I got a letter saying if I was experencing a loss of power, or bad fuel econ., I could bring my truck in because they where having trouble with the injectors leaking so ask your dealer about a recall.

They are replacing all the injectors and an oil change just in case there is any diesel in the oil.