okay so when i crank my truck and start down the road (five speed by the way) my engine runs perfectly, but after about five miles of driving it seems like when i take off my truck seems to act weird and then only run at half the power, and then ill have to press my gas pedal about half the way down just to run 45 mph, then it seems like it starts to fire the right way and ill be running 70 mph, only to loose this power if i have to stop and take off or slow down and drop rpms because of a slower car, its a 8L V10 dodge ram 2500, i hope someone can help me