Mike,
When you say original backup file, do you mean my original truck's program or the the tune of my predator? I have a 1999 Silverado Z71 4WD with autotrack and a 5.3L. My predator is a u7198, #157846. I have been running the 87 Oct program. The only modification to the truck besides the tuner ...

I am having the same problem with my 1999 Silverado with a 5.3L vortec. But, the problem comes up sometimes even when I haven't been driving hard. I have to stop and turn off the engine and wait for 10 to 15 seconds and then restart the engine. The trans will shift normally. I have tried several ...