Hi,
I have a 1988 F150, 5.0, dual tanks, I am having a problem with the fuel guages on this truck. The front tank pegs the "E" side and the rear tank pegs "F". I know I have at least 10 gallons in each tank and the truck seems to feed ok from each tank. The fuel pressure running is about 38psi on both also.

Does any one have an idea on what might be the problem here.

Thanks,
Larry

 

One is open circuit and one is either stuck full position or shorted.
Their simple variable resistance circuits.
Check for a problem at the change-over point for the fuel gages.
Meter the resistance from each gage unit to see what the condition is.
Last I knew you could not buy just the gage parts in the tank without the whole pump.
Been thru this several times with Rangers and Bronco IIs.
The thing is to make a decision to fix it right or you will have the same type thing all over again in the future with the hassle of taking the tanks down etc.
Good luck.

 

Start by measuring the senders' restances at the tank connectors (DISconnected). If they read within range (160 Ohms = FULL; 16 Ohms = empty), you don't need to do anything inside the tanks. Work forward toward the tank switch & the gauge.