Today we were messing around with my Dad's truck and he wanted to try my old Predator tuner for a few miles. Installed the 100HP tune, ran it around, everything fine then he wanted to take it out. Killed truck, turned everything electrical off, set park brake, plugged into the OBD11 port and went our way. While waiting, my Dad said he might like to try the Tow tune and leave it on there for a while. So, that's what I did. Finished and the Pred. said to unplug it. Did that and truck fired up and belched then died. He got scared and I immediately restored his original backup. Truck still won't start for anything. It just spins freely and does not even hint at starting. Checked all fuses under dash and the fuel pump shutoff on passenger side. Nothing I can find that is obvious. Are there any maxi fuses under the hood on this '03 6.0? Need help fast, he needs to leave tomorrow morning. Also, I thought maybe some sort of glitch might have occured, so we unhooked the battery terminals. How long does it take to clear memory? Been unhooked for some 30min. and when I re-connect them, the radio still has presets. Please help us!