Pressure in fuel tank

There is a large crush zone filled with air in the top of the gas tank, so gas cannot be up there and it cannot leak out there. Even if it could, the tank is sealed to prevent fumes from evaporating. 1996 and newer vehicles have a means of detecting leaks in the tank and fuel vapor recovery systems. The check engine light would be on, and there would be a diagnostic fault code related to "small leak" or "gross leak". I sounds like the EVAP system purge solenoid is not working, here is the location so you can replace it to fix the problem. Check out the images (below). Please let us know what happens.