I know this is an old post but someone may benefit from this. I had the exact same problem.
Ford did a recall on the fuel tank selector switch. Take it to a dealer and he will replace it free. I had it done to my 89 E-150. It works great now.
Also if your having problems w/ fuel tank level guage not working or working for a short while after you fill up from an empty tank you may have a leaking float bulb inside the tank. I had to replace both of mine!