Gas leak?

[7up]

Today I was driving home, my car running just fine. I get home and I swear I smell gas when I get out. I look behind my car and there is a little stream of gas behind where I pulled up. I look at my gas cap and I can hear my tank trying to suck in air. My cap is also a little loose. I open my tank cap and the air rushes into the tank for a couple seconds. Not just a tiny bit like when you run your car real low and you go to fill it up, but a lot of air goes rushing in there, plus my tank is 3/4 full. I think the gas was coming out of my tank cap because there is gas in the lip beneath the cap outside the tank and it looks like that is where the gas was leaking out.

So after this happened I decided to take my chance and see if it did it again, and it did the exact same thing except the cap wasn't loose this time. It still leaked.

So at least my tank isn't leaking, but does anyone have any idea what is going on? It is like the air is being sucked out of my tank and gas is being forced out my tank cap because of the pressure.

Thanks for any ideas, Mark