I was going to say it sounded like an ECM issue. That 1/4 throttle thing kind of points that direction. I know some of the old MADS ECM's used to do that, they would fuel just as hard or harder at 1/4 throttle as they would at full throttle. I haven't heard of the smarty's causing that too much. Glad to hear you got it figured out.

I have a drag comp (read hotunlock) on my truck and my buddy has a normal comp on his and we switched boxes, and man, what a difference. My truck felt like a dog and his was a totally different beast with it. Makes a huge difference.
Sean

 

Yeah it is way different on 6 compared to 5. Going to maybe dyno next week to see if there is a difference between the 2 or just the way it fuels.