I have a 1994 v8 SLT and the fuel gauge in the dash would work up until the quarter mark and it would show when it was anything below that and if it was empty the indicator light came on but randomly it changed to saying the fuel level is full and does not ever move and the indicator no longer comes on, is it in the dash? or is it a relay? or do i need to replace the in-tank fuel pump? Thank you.

 

Common problem on these trucks. My guess would be you need to replace the in-tank fuel pump/sending unit.

 

Try this, get about three bottles of Techron fuel system cleaner from the auto parts store or Walmart, use as directed for the next three tanks and see if that helps. (Fuel deposits can hurt senders.) Cheaper than a new fuel pump, filter, and sender and can't hurt to try.

I'm suspecting that our oxygenated gas with corn alcohol is probably responsible for screwing up you fuel sender & you'll probably end up replacing the whole shootin' match.