Mazda gas tank question?

i have a 1998 mazda protege and the gas tank is said to be 14.5 gallons from Edmund's.com. However when i fill it from e to f it is only about 11gallons that it takes. So does that mean that it has a 3.5 gallon reserve and the gas Gage only shows the 11 gallons. Any input would be very helpful. Thank you

However, 3.5 gallons is a lot, especially in a small tank. It's possible that the fuel level float in the tank may be out of calibration, thereby giving an artificially low fuel level. I had a gas tank replaced in a 2001 Hyundai Elantra and the gas gauge was never quite right at the low end after that.

Edit - Are you asking about the replacement tank in the elantra? That's kind of a moot point since you're driving a Mazda. The point I was trying to make was that the gas gauge reading was erratic after the new tank was put in, indicating that the sending unit in the tank was somehow flawed. Maybe you’ve a similar flawed sending unit problem??