Since rebuilding the trans on my 07 Z71 4wd nbs 6.0 max pac truck with a little looser convertor, the shop retuned and I went to the track going from a previous of 15.2 @ 92.5 to a 14.8 @ 91.80.

The truck is a lot better off idle, but it lays down as it approaches the shifts, especially going into 3rd, where it darn near feels like it's going to completely give up, belches (figuratively speaking) then shifts and goes.

I'm not sure if it's a fuel issue or the shifts are to close to the limiter (5800) or what. Any ideas? I'm guessing we're leaving 2-3 tenths out there and another 1-2 mph. It also sets the anti locking brake light (yellow) when shifting to 2nd. On the hiway when punching it none of these issues occur, and have not previuosly. 110,000 miles.

Truck has LT's-cat back-cai-dyno tune. Ideas??????

 

Did the tuner, remove all the engine TQ management, and some or all the trans TQ management??

 

i got a simular problems with mine except its the 1-2 shift, im all stock wot its fine just off ide is fine t/h is fine theres jut a spot n throttle where it does it.. there is a tsb for the tcm dealing with mine says need replace or reflash.......u prob got to much tm takin out....just my 2 cents havent done ne tunestuff so im an idiot to it.(no smart *** comments please)

 

The previous tune had all but 10% out if i recall correctly. I'm not sure what this latest tune has done with tm, but it does feel like it-only worse.