I have a 1999 4Runner, 3.4, 4X4 Limited. Last week my gas guage started acting up. When I start the truck, the gas guage is topped out at "full". After 2-3 minutes of driving, it bottoms out at empty and the low fuel warning light flashes continuously. The fuel door open light doesn't seem to work either. I have pulled all of the fuses and disconnected the battery hoping that something might re-set itself and fix the problem, but it didn't help. Does anyone have any thoughts on what might have happened and how to fix it?
Thanks. Wesley Preis

 

Sounds like fuel sending unit.

:wabbit2:

 

Agree. I had the same issues. FSU was bad.

 

What Gas did you fill with last? 5 years ago Shell Oil had reformulated their fuel because it had too much sulphur in it. That was causing fuel senders to malfunction. shell seems to have fixed their fuel issue but others may be bad still.

I use almost exclussively Mobil gas 87 oct. The one time I used a cheaper gas, "Speedway gas" 2 months my gas guage began reading a full tank at 3/4 on the guage until all that gas was used up.

Before you start replacing parts, run the tank dry and refill with a premium fuel from a big oil company like BP, Mobil, etc. that fixed mine and it hasn't acted up since then.

 

Fuel door open light? I don't believe that door is wired electrically in any way.

 

I don't know. Mine has an indicator light that lights up when the fuel door is open. It says "Fuel Door" with an arrow pointing to the light.

 

I'm an SR5 trim 3rd gen. Perhaps the fuel door open light is something the Limiteds feature.

The indicator on the gauges is to indicate which side of the vehicle the fuel filler door is located.