Is it normal for no pressure to be relieved when I remove the gas cap? It seems like I never hear it hiss when I remove the cap, even if I have been driving for a while. Could I have a leak somewhere?

 

Before I did my V8 swap, mine would not his, ever. After I did the swap it would hiss everytime I unscrewed it. But recently it just stopped doing it. so

 

If it is stock it is not supposed to. There is a vent and also a charcoal canister, that is supposed to store those vapors to be used by the engine.

Now if somebody started farting around and screwing with stuff....

 

Ok, so there is not supposed to be any hiss when you open the cap? My car does have a hiss when I open it... what could cause that? You said a vent or charcoal canister? More details please... caues my car hisses alot when I open the gas cap, and I also have problems with the car stalling once in a while... maybe they're related.

 

so its not supposed to hiss when stock? thats weird because there are 2 other thirdgens in my family and they both hiss when I gas them up. I was just wondering if it had something to do with my crappy gas mileage.

 

I think were talkin about the evaporative emission canister. When I did the swap I got rid of mine, then it would hiss. Poor idle or stalling can be caused by an inoperative purge valve, damaged canister, split or cracked hoses or hoses connected to the wrong tubes.