The mega cab with all the mods in my sig is the truck I am having this problem with. I have recently detuned the truck and now it only has the smarty and a goerend trans. The truck surged with all the stuff on, but I just assumed that was part of having all the parts on it. It ran great and still does at WOT. But just cruising, it surges pretty bad on level 8 and 9. I tried 6 and 7 and it does fine. The speedo is also acting up. It also done this with the mods and still does it. The speedo when sitting still, only goes down to 3 mph istead of 0. And when moving, it jumps 5-8 mph instead making a smooth sweep. Like cruising at 70, if you accelorate to 80, it won't move in 1 mph increments, it will jump from 70 to 75 or 6 then to 80. And on decel, it will stick at 80 until you drop 10-15 mph and then start moving. I just wander if these two problems are related. Never had a smarty problem since I've been using them until now. And this thing smokes whether taking of easy or hard. If you take off normal and just accelerate normally, it smokes pretty good through all the gears. Sorry this is so long, just wanted to see if anyone has seem these problems.