Excessive Gas Tank Pressure when it's hot outside

[ew1usnr]

I noticed a steady drip of gasoline coming from right behind the bumper on the right side. After spending a few minutes under the car, it looks like the gas was coming from some sort over "over flow or vent tube". On a hunch I removed the gas cap (which has been mounted inside the trunk for well over 3 years now) and when I gave it the final turn to the cap to remove it I heard a healthy "whoosh" of air come from inside the tank as it had ballooned (due to too much the pressure in the tank) and then the tank went back flat in the trunk.

That is really weird. Hot pressurized gasoline would scare the heck out me. I would leave the trunk open, the gas cap loose, and roll the car out of the garage until you figure out what is going on.

On a stock Falcon, I do not know how the gas tank would be ballooned out unless the vent tube was blocked. I do not know how gasoline would be dripping out of the vent tube because the vent tube rises higher than the filler spout. The gas tank will overflow from the fill spout before overflowing from the vent tube.

I cannot explain how the symptoms that you have described could occur.