from the time i bought a 96 GS i usaully wait till its almost empty, and ive never got more than 13 gallons.? so i thoughts that was what my tank was. till i saw on the net that is like 16 or sumthin.??? and i realized im gettin shitty gas mileage, and my gas gauge is off. ne one else's gas gauge off. car runs great, im gettin like 16 mpg. ne advice

typically the low fuel light comes on when there is 3 gallons left.
and if you have bad gas milage I would look into a tune up and more specifically changing out the upstream o2 sensor.

My AWD's have a 15 gallon tank and I would imagine yours would be about the same. The most I ever filled was 15.2 gallons, and I was literally running on fumes (new to me car, broken fuel gauge). Also, 16 MPG is not good at all! I can easily get 23 on my GSX, and I don't like to drive too slow :) I agree with /\ that you should probably replace your front O2 sensor. If you search you will find more reasons why you will get bad gas mileage.