Any one have any ideas what might be wrong and how to fix it?

More than likely the wires to the fuel gauge (which is in the tank) have rotted faulty (common with this truck).

I was going to type a whole thing out, but I just found this: WikiAnswers - My 1995 ford ranger fuel gauge isn't working how do i trace the problem

:) good luck

I had a broken fuel gague in one of my cars for years. Every so many miles I would stop and fill up the tank. If this is an expensive fix for you, would suggest that you just write down your mileage when you fill all the way up and then go only 150 miles tops between filling it all the way up again. Don't cheat and just add a few gallons here and there otherwise you will run out of gas. If I could do it for abou 4 years without getting it fixed, so can you (if you are on a tight budget).

U used to have a thick piece of wire with masking tape on the end. I would feed it down the gas tube... then pull it back up. If I had gas on it.. I knew I was OK for a while still. Lol

It might not cost anything but time... if you have to replace the sender. Could be pricey

I had to replace my fuel pump and it was located inside the gas tank. Had to drop the tank to replace the fuel pump. The new one I got and installed has a wacky sending device in it. I'll keep reading a full tank of gas even after I have gone over 100 miles, then the needle drops sharply to read under 3/4 tank. I just watch my mileage driven and gauge accordingly. As you can see, I've had little and no luck with fuel gauges in my cars and I don't trust them one iota.