I recently picked up a Superchips 3950 cortex for my 4.7 for a decent price, still had a half tank of 87 and tried the 87 tune. Gas mpg actually seemed better, engine sounded different and the 45rfe shifting is worlds better.

I filled up on 93 and tried the performance tune and for some reason I seem to have different results than most report. I actually feel like I lost power under 2000rpm's, and my mileage is slightly worse as well. I never got to go WOT on the 87 tune but I did after I installed the 91 tune, and holy hell did that little 4.7 pull like a mother. Spun the heck out of the tires too!! Driveability on the 87 tune was better though so once this tank is burned I'll re-install the 87 tune.

Anyone else have negative results running 93 in these trucks with a programmer?