And yes i have searched but haven't really gotten a straight answer. I received the truck from my dad after it had sat about 2 years getting driven very rarely. The fuel gauge didnt work since the day he gave it to me but said it always worked for him. It started leaking really bad out of the selector valve one day and i went and got one from a junk yard the problem still is there. The fuel tank selector switch works because i ran outta fuel in the front tank the other day and hit the switch and fired back up. The gauge reads full all the time on either tank. About a month ago it had ran out of fuel on the front tank so i switched to the rear i flipped the switch back to the front after it sat for a few days then it read empty. I'm so confused idk where to start. Any help will be appreciated. Thanks

 

I had this same problem here:
https://www.f150online.com/forums/pr...tank-woes.html
In it, steve83 posted this, it may help:

 

That only proves that the pump half of the switch works - the gauge half could be totally shot.

 

I will try a switch out of another truck see if that helps! Thanks for the fast replies and advice..Its so annoying not having a fuel gauge

 

Well ive yet to try a new switch because i cannot locate one around here. Ive been running it on the front tank and just filling up every so often. The front tank started leaking bad one day and now the needle on the front tank reads empty. but way past full on the rear which im useing now. could this be a faulty fuel level sending unit?

 

its the sending unit in the gas tank(s). I Had the same problem in my '86. It's part of the fuel pump, about $150.

 

hello all. i am new to this .. i have some what of same problem, gauge is stuck on full. back tank is shot i believe. has varnish in it.. can i plug it off til i get new tank..froint one is fine gauge is not working at all..its a 1988 f150 custom .. if iam in the wrong thread, sorry.can you point me to the right one.. any help would be great...

 

Did you read this thread & follow the link in post #2? The gauge is virtually independent of the fuel pump (although the sender is attached to the pump tubes), so read these captions to see how to repair the sender:



Your pump is slightly different from that, but the sender is the same. These show how your fuel system works:



These explain how the gauges work:



You don't need to plug anything - just leave the dead tank alone. When you get ready to look inside it, read the captions of the relevant pics in this album:

 

hello, steve83..and others.. thanks for the info.. i think its best for me to go to a shop to fix this.small stuff is ok..this is outta my repair range...thanks again