My car decided to puke out some gas today, after a little bit of driving. Something isn't venting right, since it came out from around the gas cap. I had only been driving for ten minutes, and it's about 70 degrees outside right now. I have about 17 gallons in the 21 gallon tank.
Dafuq? Anybody know what the heck could be going on?

Also, the holidays are approaching quickly. I get to use the trunk for it's righteous duty again!

 

It could be that the actual vent for the tank are blocked by something. Usually 2 at the front or sometimes rear of the tank. On the top edge.

 

It could be the actual vent lines are dried, cracked, and leaking.

 

Yes, this sound like a classic clogged vent problem. Get under the car and find the gas tank vent tube or tubes and make sure they're open. On my '67 Delta 88, there are two, and they each have about a two-foot length of rubber tubing attached that is routed up above the tank and attached to the body just above the rear axle. This gets the level of the vent opening above the level of the tank so no gas can leak out. The vents are located on the front right corner of the tank on my car.