Fuel Gauge Observations (96-98)

1. With the nose of the vehicle facing down an incline, the fuel gauge can read as much as a 1/4 lower than what it actually is (whether this can trigger the fuel light is still unknown to me). The severity of the discrepancy depends on the incline, it doesn't have to be that steep to change the reading
2. The opposite is true to a lesser extent when facing up an incline
3. The gauge will take its time to show a full tank of gas again after filling it up and starting the vehicle
4. The gauge is static so it will display the current fuel levels even when the vehicle is turned off
5. All of the above observations are completely normal and is just how the gauge behaves

Supposedly in 1999 Toyota made changes to fix the fluctuations in fuel levels readings caused by inclines. I've seen that on 2002 4runners the gauge behaves more like one on a modern vehicle, it no longer displays fuel levels when turned off, and it will show a full tank the moment you turn the key after filling it up (when this change was made IDK could be 1999 or when the odo was changed to digital)

 

My 87 4Runner does that, but only when the fuel level is down below 1/4. It gets low enough, stepping hard on the brakes will make the light come on, then go off again after it stops and everything settles. Or stopping on a downhill will do the same thing. Once I put enough fuel in to go over 1/4 it stops.
My 87 pickup used to do the same thing, but the fuel gauge quit long ago. It goes below 3/4, it drops to zero and stays there. The Light still works fine.
The 99's fuel gauge just seems to indicate whatever it feels like at any given time.
They all drop to 0 as they should when the key is turned off.

I don't know what it all means, other a set of 3 bad sensors. I just haven't bothered to replace them. Maybe someday. As it is, we just keep an eye on the odometer. All things being equal, I understand most manufacterers make their gas tanks to take the vehicle right around 250 miles, so we get to 200-ish, time to fuel up. Hasn't failed us in 30+ years of owning these trucks. At least the 87's. Only had the 99 a few months now, and it's been in and out of shops most of that, just fixing the little things fleet vehicles develop over the years. Great engine/drivetrain maintenance, not so good about the rest, but it's almost back to factory, now. Once I take the time to replace the sensor(s)...
Thank goodness they put the little hatch in the 4Runners. I dread doing the pickup. I may just leave it, and let my middle daughter's 3 sons deal with it when I'm gone and she get's the truck. And she will. I taught her to drive in it, and she drove it when she was stationed at Camp Pendleton, and now she demands, in a daughterly way, that she get it some day, so she can teach her sons to drive a stick in it.

Anywho, there's for our trucks, for whatever it's worth...
Pat☺