I got to 1/4 a tank of gas and went in to fillerup on my 2001 Toyota Sienna with 243xxx miles. I was already home (one mile) and the fuel gauge had only just gotten to within one needle's width of the full line. I watched it slooooooowly rise. In other cars I've had, the gauge would already be at the top (or jump to the top when I started the car) before I got in the car.
Does a slow fuel gauge indicate something sinister? Or, should I just not worry?
All this means is the sending unit in the gas tank is starting to wear out. It's a potentiometer attached to a float with a wire arm, and works similar to a dimmer switch in fancy dining room lights. Slide it up, it gets bright, slide it down, it gets dark. In the gas tank, the really bright setting gets interpreted by the gauge as full, and the really dim setting is seen as empty. That's perfectly normal to have wear out over time, it's been in the gas tank 20 years and subjected to constant heating, cooling, freezing temps, getting jolted by bumps, etc. Just keep an eye on your distance driven between tanks, and you'll be ok if it dies. Worst that happens is you could run out of gas. Replacing it would involve replacing the fuel pump as well, since that is all one unit in the tank.
