No ideas ?
Is there any way to see if the truck has already been tuned and that is what the problem is ?

Yes . I have been installing the Diablo 87 tune to the truck then coming inside to download the saved original tune to the computer . Then I upload the new custom 87 tune to the Predator and installing that on the truck . The only difference I see is the original saved files are 330 kb vs 262 kb for ...

Hello . I tried the new tune today . Well now it won't idle correctly . I fired the truck up and the idle hunts from 300-1500/2000 rpms and back . Then it seemed to stabilize at 500 rpms . Backed out of the driveway and go forward and ....nothing . No throttle just 300-500 rpm idle speed . Backed ...

So I had time today to try the new tune . Still idles perfect still won't go . The truck wont accelerate past 1500 rpms under load so it won't shift into 2nd . If it shifts into 2nd it will accel ok but if it downshifts no go . I just drove around the block as if it won't accel in low I didn't want ...

So no luck on getting this to work ?
Is there a product available that will work with the 8.1 ?
What do I do with the predator that I can't return to the store ?

2004 GMC 2500HD with 8100 Vortec Allison 5 speed
Predator U7193x
Updated to version v.9r11 May 4 , 2012

I first removed the 3 fuses as per the instructions . Installed the 87 tune with no mods to any parameters . Started truck and it had surgy idle . Tried driving the truck and it just falls on ...