Cause of high fuel vapor pressure??

[Pitviper1996]

have a 94 gt and everytime i get gas and take off my gas cap theres alot of hissing when i unscrew it due to major vapor pressure what can this be caused from and will it harm anything?

[Jeff88coupe]

Heat in the fuel system is the biggest reason...but no...it will not harm anything. The fact that you hear it hiss when you take the gas cap off means everything is working correctly.

[Pitviper1996]

well only reason it concerned me was because it isnt a slight hiss it slmost seems if i didnt take it off slowly the damn cap would go flying

[80 hate]

Is it the stock gas cap?

[Pitviper1996]

no i bought a new one and put it on there