I heard that Ford de-fuels the diesel at some speed. I have had mine to 85 and no problem. What speed does the computer de-fuel? Is SCT the only programer that will eliminate this? I was minding my own business cruising at 70 mph at 1950 rpm, and a Dodge Cummins passed me. I went up to 85 and passed him. He faded back. Then I thought, what if I pushed it past 85, where does it stop running?