In response to my fuel tank overpressurizing and pushing gas out the (new) cap, I am replacing the charcoal canister and all of the rotting vacuum tubing connecting it to the purge valve and intake. When I removed the lines, I found that I could not blow or suck air through the vapor valve on the tank. Should I be able to? I am planning on putting a vacuum tester on the valve after removing the gas cap, but I am not sure what it should hold.
Any help is appreciated. -Cletus

Forgot to add that it is on a 93 GT.

 

Update: When I dropped the gas tank to replace the valve, I found the rubber line connected to the valve had been pinched between the tank and the trunk floor-pan. New line, problem solved!