do you hear any air excaping when you take off you gas cap? mine doesent make any noise.all the other cars i own do..may need new cap.

 

i hear mine sometimes but most of the time i don't hear it at all.

 

 

I don't hear any air escaping, but my cap is a POS. You will know if it isn't sealing because you will get a CEL light. I got one the first week of owning my car and the culprit is the cap itself. Even with 3 clicks it isn't tight, so I have to grasp it around the edge to get it tight.... and yes I know this is a cheap part, but I am a lazy lazy man.

 

It's designed to keep all vapors in. That's what them green-brained tree-huggin' hippies insisted on. Then car manufs had to come up with the whole EVAP system. That's what the canister is for - to keep vapors in until the car is started. Then secondary air injection pump kicks in, vapors are released through valves into yer intake manifold, etc.