'93 gas guage drops to Empty

I'd say your float is leaking.

Ford picked this truck as the one that they are able to supply just the brass float for. Lat time I looked the part is less than $10 at the dealer.

To change it, you'll want to drain the tank and remove it. It's not as tough as it first looks, with most of the brackets and bolts prety obvious as you look up from the bottom. Get the truck up high on stands so you have room to get the tank down and slide it out next to the car once all the pluming and wiring are disconnected.

The plumbing-and-wiring list includes the filler neck hose, that the big one running from the gas cap down to the tank. Hose clamp, twist the hose a bit and pull the hose off the tank. There are hoses from the front of the car, the pressurised line and the unpressurized return line. Before you can get the pressurised hose off, you'll want to bleed the pressure out of the fuel system through the fuel pressure test valve on the engine, right (passenger side on US cars...) fuel rail at the base of the maniold, forward of the ignition module, little black cap over what looks like a tire valve. Bleed off the residual pressure there. The connection at the tank is one of those garter-spring connectors like the one at the fuel filter, so you'll need that fancy little tool to get that hose off. The return hose comes off easily.

The electrical connections are for the fuel sender and the electric pump inside the tank. Take those off and you should be able to continue lowering the tank to the ground.

The pump and sender are held in the tank with a lock ring that engages tabs on the tank. You can see how it rotates clockwise to lock. Ford has a fancy tool per the WSM, but I was able to get mine off with a few taps of the small hammer on a wood drift (piece of wood...) to rotate the ring. Tougher if it's rusted on there. Once the ring is off, the sender/pump assy lifts out, and you'll see the float on the end of that wire arm. The old float rolls out of the curl in the wire, new one rolls in.

Then of course, assembly is the reverse of disassembly. I went through a couple tries getting all the brackets and the skid pan back on there just right. I'd probably take a few pictures or at least draw a diagram or something if I was doing it again.

I used a floor jack to support the tank as I disconnected atnd reconnected the plumbing and wiring. A milk crate worked better when I did another one.

Before you start the work, disconnect the battery. Work outside away from the house, fire extinguisher ready, charged garden hose, etc. No electric power tools. Wear gloves and don't get fuel on yourself. Make sure the tank is really empty before you start. Wrestling a tank with a gallon or two of sloshing fuel is way too much fun, and dangerous to boot. Make sure you clean the top of the tank of all the road debris before you pull the sender/pump out. That way you won't need to clean the tank out before you put it back in.

Check for leaks before you drive off. There's no such thing as a "small" fuel leak.

My total time was a couple hours for this task, including set-up and cleanup.

Cheers!

dr bob