Gas gauge stays at half, but fuel light comes on when needed at low fuel level

I would think maybe the fuel float is stuck being at half tank, but If the fuel light is coming on when it’s needed, would I be looking more of a problem at the gauge?

 

Might be the float is independent of the low fuel sensor. Sensor still works, float is stuck? Someone who knows more will chime in.

Whether the "always fill up at 1/4 tank because the fuel pump is cooled by the gas" advice worked for me, or I'm just lucky, my Tacoma with 330,000 miles is still running the original fuel pump, so I've never had to drop a gas tank. Don't know exactly how it's all set up.

I guess it could be a problem at the gauge, too. When it comes electronics, things can get weird. I've had vehicles with sending unit problems, where they were wonky, but weren't completely inoperable. They never stayed in one place, like at half. Usually they worked at full, then dropped to empty after 20 or so miles.

 

The sending unit is essentially a variable resistor, which tells the gauge how to read. Think of it as a bit of rust on a stick, with a wiper attached to the float that slides back and forth as the fuel level increases/decreases, change the resistance reading proportionately. This is a hideous oversimplification, of course, but the point is that it's a mechanical device, and after umpteen cycles the rust flakes off, leading to intermittent or partial readings. Therefore, I would suspect the sending unit first and foremost. You can check this hypothesis before you drop the tank by getting a known good sending unit and connecting it outside the tank. You and a helper can manually move the float back and forth to confirm that the gauge now operates correctly. If so, drop the tank, install the new sender, and install a new Denso fuel pump as well so you never have to drop the tank again. (Unless it drops off by itself...don't ask me how I know this).

 

Or just use your trip odometer for a fuel usage meter of sorts.