How to vent gas tank

[1983foureyegt]

I’ve recently purchased a 1983 Mustang GT and when I went to the gas station and opened the gas cap there was a lot of pressure built up that came out when I opened gas cap I’m wondering what to do about it , it can not be good for there to be a lot of pressure built up my my gas tank
Thank you for any help not really sure what to do

 

[billison]

I owned a 83 like... 20 years ago so my memory might be off..

But there should be a vent tube already... people like to cut them and plug them because they don’t understand the basics of cars and ( racecar)

 

[1983foureyegt]

I owned a 83 like... 20 years ago so my memory might be off..

But there should be a vent tube already... people like to cut them and plug them because they don’t understand the basics of cars and ( racecar)

Thank you, from everything I can find it should be vented but I do not think it is because a lot of pressure is realesed when opening the gas cap and I’m having a hard time figuring out what to do to fix it, also does anyone know where to buy a vented gas cap, I cannot find one

 

[General karthief]

http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg
http://www.veryuseful.com/mustang/tech/engine/images/88Stang5.0Vacuum.gif
These links will give you an idea of what is involved and what to look for, it is a closed system, the purge canister should be under the hood on the passenger side frame under the air box.

 

[Mustang5L5]

Vented gas cap

 

[1983foureyegt]

Vented gas cap

Thank you, but do you have a link or an idea of where to purchase one I wasn’t able to find one online anywhere