The simplistic Ford Gas Cap has more responsibilities than what most owners know of. The gas cap on the inlet section of your Ford fuel tank not only keeps debris out of the tank, but the hole in its makeup also vents the fuel tank so excessive pressure does not build up in it.
It is this vent in the Ford gas cap that has to function all the time for your fuel delivery system to operate as it is expected too. The vent is actually just a small hole in the center of the gas cap that generally goes unnoticed. It can become clogged if the cap is old and rust accumulates on it. The owner of a Ford will notice there is a problem when they go to remove the cap and it pops off. When the pressure is really built up in the fuel tank it has been known to fly off when released from its hold down position.
Because of the way the gas caps are designed today, just cleaning it of rust will not always clear the vent hole and it might have to be replaced in order to function properly again. The danger to your vehicle is if this condition is allowed to continue is the premature wearing of your fuel pump. The excessive pressure can also break the seals in it and it will place unnecessary stress on it so it will fail before its time is due. It can also cause a breach in the fuel system causing a dangerous spray of fuel to exit it.
The wondrous simple little gas cap. It is more important than what most Ford owners think.