I have a 2004 Chevy 2500HD with the Duramax and Allison trans. The other day I had an issue with only being able to get about 2000 RPM out of the engine. Anything more than that it would buck and backfire. I replaced the fuel filter and air filter and it ran fine. I put about 250 miles on it over the weekend, then Monday morning it started acting up again. I tried priming the fuel filter again and now it won't even start. All this with only about 64K on the motor. Anyone else have this problem?

Try chaging the fuel filter again, possible cracked filter housing causing it to suck air.

or forgot to get all the old o rings or gaskets out or the plastic bleeder plug cracked or o ring isn't on right or...just a lot of stuff to make sure is right