What causes power loss in a 1990 gmc 3500 3speed when going up any kind of incline or small hills can be doing 60mph and bogs down to about 30mph
Sounds like something in the gas tank is being sucked into the fuel pump filter.
yes..first check/change fuel filter/pressure...
Make sure to check transmission fluid. Is it full? Clean? etc.
What was the problem? I'm sure you've figured it out by now! lol