I am having what appears to be pressure build up in my fuel tank. When I take the gas cap off I hear a whooshing sound. I thought it might be vacuum but after sticking my nose down there, I do smell gas fumes exiting the tank under pressure. The car seems to run fine, but I know this is not normal.

1. Does anyone know what would be causing this build up in pressure?

2. What would be the correct cure? Vented cap, some kind of pressure relief valve or what? I did ask about a vented cap at the auto parts store and got two responses: A.) we only have a listing for a non-vented cap for your 1984 Firebird and B.) a blank stare like I had just asked for a replacement spleen.


Hopefully someone has had this happen before and can provide some guidance. Thanks for any help offered!
Brad

 

Mine does it also. There is a vent tube that is suposed to relieve pressure, it may be cloges up. Unless it is building enough pressure that gass isent flowing to the motor i wouldent wory about it.