2000 S10 fuel gauge
 

I have a 2000 s10 and the fuel gauge doesn't move off of full, is the sending unit in the tank more then likely the problem

Yes, 90 percent of the time in my experience. I have never tried this at all, but Techrom Complete fuel system cleaner has been known to free up contact points, but
not always by a long shot or so I have read. If it did work, it sure beat dropping the fuel tank and putting in a new fuel level sensor ( and might as well change the pump)
and less costly as well. Could be the float is stuck. Might try a rubber hammer on the tank and see if that works.

Thanks for the help