Hey I'm new to this forum and diesel's. I recently bought a 2004 F250 6.0 Turbo Diesel. Upon purchasing I changed the oil, oil filter, fuel filters and coolant filter. I installed a Bully Dog GT Diesel today. Installed with no problems test drove fine. With the bully dog on no power level I drove to my uncle house and about halfway there I got a Defueling Coolant message on my bully dog and truck would not accel and brakes were also hard. Pulled over to the side of the road and shut the truck off and started it again and everything was fine. The default defeuling temp is 210 the temp was reading about 218 before shut down. When I got to my destination I restore back to factory settings and the coolant temp never went about 195 the oil temp hit 204 but that was it. Does anybody know the cause of this and I was only driving about 50-60mph.