Originally posted by Andy
Aside from making sure the key is off, you should open the gas cap and let some of the pressure out. Ever hear it hiss before you fill it at the pump, that pressure you didn't let out just sprayed out from lines when you opened them. You'll be fine but make sure you clean everything up and keep the gas off the paint (can damage it). Seeya.
I think you are mistaken my man, that is vacuum in the tank that you are hearing. The emissons system uses a purge canister to get rid of the vapor in the fuel tank. Gas vapors are explosive, gas is not. So they suck all the vapors out of there and run it through a charcoal canister.