* Inaccurate fuel gauge: Fuel gauges can be inaccurate, especially as the vehicle ages. A faulty gauge could be reading lower than the actual amount of fuel in the tank.
* Misinformation: Someone may have incorrectly reported the fuel tank capacity.
* Modified fuel tank: It's possible the vehicle's fuel tank has been replaced with a smaller aftermarket tank, though this is less common.
To determine the true capacity, checking the owner's manual or the fuel tank itself (often stamped with the capacity) is the best way to confirm.
