hey there. i have a 01 f450 with the 7.3 diesel. today i started up the truck and the check engine light was on. i tried to start off in low gear but the truck could barely go forward like all power is gone. and the truck wont go over 1500rpm. also the speedo dont work now. so i just had to leave truck parked and couldnt bring it home. any help will be greatly appreciated.