'97 F350 Powerstroke w/auto. When starting truck when cold, the truck fires up just fine. But when you drive, there is no power and a ton of black smoke pours out. As soon as the temp gauge hits the 'r' in 'normal', it's like someone threw a switch and the truck runs fine. If you plug the truck in the night before, I don't have the problem, it starts and runs right away. Any ideas?