Ok I have an 05 Crew cab z71 5.3 with cold air and thrush muffler thats cutoff right before the rear axle with stock size maxxis mudders.. What I wanna know is why does my truck one day burn the hell out of some tires and sometimes it just sits there and revs up high not trying to do anything?? Like the other night I got a lil stuck on a turn road so I locked it in 4 high and put it in reverse and would not pull a tire for anything, just sat there and reved up.. I got off of it and finally got back on it and it started pulling then. What causes this issues?? I am taking it to memphis Jan 9 and let blackbear tune it, hope that will help out.. BTW I am not throwing any codes either..

Also I was wanting to know how much HP will a custom in person tune will free up over stock?? Thats with the 5.3