I have an 84 GMC 6.2L in a crew cab dually that I had replaced with a new factory crate motor 10 years ago that runs fine around town, but when I head out on the Fwy and start to climb a big hill (west coast) it will start to lose power and the water in fuel light comes on and the engine temp gauge starts to climb above 230 and if you let off the power and slow down, the light will go out and the temp go right back down to normal? I just finished a 700 mile round trip and it runs great other than this problem... Anyone have any ideas????
Thanks, Louis