Weird gas tank story?

[Phoenyx]

OK, so last night I was heading home on empty. There's a gas station a block from my house, so I was just gonna get gas there. About a block before the gas station I heard a pretty loud bang come from the rear of my car. At first I thought maybe someone threw something at my car. When I got to the gas station I checked the car over and couldn't see any damage anywhere. So I then went to put some gas in. Then as I went to fill gas I noticed something. As I unscrewed my gas cap, it seemed like it was under vacuum. A lot. And as the air was getting sucked back into the tank, I heard that bang again. So I'm guessing it was the tank flexing. I have never had this happen before. Is this normal?

 

[shotgun]

Gas tank oil canned, pop.

A vent or return is blocked somewhere.

Did you do any mods/repairs lately?

New gas cap?

 

[Crossbreed]

I have a similar problem with my Crown Vic (the gas cap pops so I need a new one, but no loud bang from the gas tank though) and was told to change the charcoal canister (that's on a Ford, so I'm not too familiar with the Regal yet). Do you have a hard time filling your tank at the gas station (does it constantly click off and spill out?)?

 

[Coveted]

I get the opposite, even with 1/4 tank, I open the gas cap, and its blowing enough air to levetate a midget.

 

[beermonkey9417]

you need to get a better/new vented gas cap.

 

[Phoenyx]

Yes I put a locking gas cap on it. It's susposed to be for a g-body. Never had this problem before. If it makes any difference, it was also on our first sub-zero night.

I don't know if the vent line is plugged. I still have the canister under the hood. Is there a way of checking it?

Maybe this has something to do with the fact that my gas milage has been going downhill for about a week?

 

[beermonkey9417]

most likely its 1 reason, because the pump has to work harder to get the gas from the tank to the carb. i would think it would make it run lean but idunno.