Fuel tank builds pressure June 16, 2018, 11:34:14 PM '83 Turbo Coupe, the fuel tank builds pressure and fuel vapor eventually gets into the cabin. I've had the tank off and don't see any issues with the lines. When there is pressure in the tank fuel vapor cannot be pulled by vacuum to the charcoal canister, relieve the pressure and vapor flows. This has me really stumped and I can't safely drive the car. Thanks for your help.