I have the same issues with my 05 and posted in the "enough is enough" thread, but no response from Diablo.

I have the Predator on my 05 6spd and noticed the same surging while cruising and the big cam lope. My truck has 114,000 miles and hasn't been touched by the dealer. Is there an update or custom program to address the drivability? I have to say, I'm not impressed with the Predator as much as I was ...

Yeah, the computer is completely wrong! I have an 05 Cummins Quad 4x4 long bed with 6spd and 'puter read anywhere from 18-22 before the predator (hand calculation typically ended up with 16.5). With the Predator the 'puter now reads 35-45!!! Hand calculation is still 16.5. I get on it occassionally ...