HELP!!!

[extra330]

Please advise, working on 04 duramax lb7, has aftermarket 4" exhaust, k&n cold air intake, and of course the diablo sport tuner. really disappointed in the gain i am seeing. the only really noticable change is the shifting. am i doing somthing wrong? even on the 120 hp tuner, no difference seen/ please advise

[mikel]

This is the first I have ever heard of such a thing.
I would suggest you check the fuel filter and the rest of the fuel system to be sure it is all up to par.

Thanks