99 SR5 2wd, while driving back from a 4 hour trip with a 6x12 trailer i just bought, the fuel gauge while at half a tank started moving back up to FULL??!!

I made it home, went to the fill up the tank, and with it full, the fuel gauge is rock bottom with the fuel light on.

Now the fuel gauge is on the bottom consistently w/ the light on.

Where do i start?

Thanks!!

Jonny

 

Replace the fuel tank module would be a good place to start.

 

Fuel gauge circuits are usually pretty simple, get the wiring diagram andfew minutes with a meter can save a lot of time and $ instead of throwing parts at it.
david

 

About 10% of the time, initially after starting the engine, it'll give me an accurate reading. Then after 5-10 minutes the needle starts creeping up to full. Then it drops to empty and fuel light start blinking.

There's been a TSB on the fuel sending unit. These are common problems. Not sure however, how to troubleshoot wiring in the circuit board. Can you or someone give me some circuit board for dummies? Even a location on where to start ie. up under the dash, or pull the dash out?

 

I'm not familiar with this particular circuit. Some autoparts chains, online or just a friendly mechanic that has an Alldata database will gladly print out the circuit for you, meaning the wiring and parts setup from the gauge to the tank sending unit. I would'nt mess with circuit boards, just use the diagram and meter to narrow it down to the part. Then again, your particular weird symtom might just point straight to the problempart, or a bulliten/recall that was issued.
Sorry I cant be of more specific help, but do keep us informed.
David