DUramax hicup

[seatec]

Got this weaird thing that has been going on for a week or two. My Truck as about 1500 miles on her and just started to exhibit this weird engine rev thing. When i moderately accelerate and the alli shift up and i let of the gas the engine revvs for a split second. It sounds as if i where to just tap the accelerator paddle for a split sec. anybody know what this is? Does it have something to do with me putting in diff kinds of brand DIesel? so far used shell,Exxon, Hess and some no name (because i had too).

[Shaners]

I'm just guessing here, but my dealer has performed miracles for me with my 6.0L gasser through reprogamming of the computers.  Maybe that is all that needs done to your truck...  GM releases updates all the time.