my fuel gauge is acting up, you never know what its going to read each time i crank the car, sometimes it pegs out at full and sometimes it reads normal. i know on older cars there is a relay behind the instruments that goes bad, but i don't think the 87-93 has it. what else to look for?
Before I replaced the sending unit (in fuel tank), the gauge would stay pegged out up until the last couple gallons, then it would come down to the bottom. Unfortunately you gotta drop the tank to put in a new sending unit, but it could be a good excuse to upgrade your pump.
The fuel level sending unit is just a variable resistor. The higher resistance means high fuel level. What usually happens it than an open in the resistor forms = infinite resistance = full tank. You can get a new sending unit from Ford or you can get it from 5.0 Restoration or some other resto places.
yep going to have to drop the tank. A good idea would be to run the tank nearly empty before you do this. And as stated above it is a good time to upgrade the fuel pump so you can continue to mod your mustang with no worries about fuel supply.