I turned the ppe up to level 4 for a road trip to see what kind of mileage it would get and how much the power increased. The mileage was alot better that level 2 or 3 and the power increase was pretty noticable. My concern is that when traveling at about 55 or 60 and i accelerated to pass or go up a grade, the plume of smoke was way too much. The truck didn't downshift and I was no where near WOT anybody have any reasons for this?