I have a 2004 2500 6 speed with 127K and at the top end of each gear, say 2000RPMs - 2500RPMs the power seems to sputter and decrease but is ok when my foot is into it? Changed fuel filter and no change? Could it be injectors? They are stock and fuel tank and fuel seem to be clean. Air filter probably needs to be changed and will be doing that to see if that changes anything.

Any thoughts?

 

Sounds like it could be the lift pump if you still have the canister mounted pump. Have you checked your fuel pressure? I would think that you should be looking in this direction over injector changes.

 

You will have to forgive my lack of knowledge of full engine mechanics but I had the pump in the tank changed and assume your talking about the lift pump at the engine which I think is internal? I have not had the presure checked but will do that. Thanks!