cfritzin

The tank is deff. not venting properly. what is the fix?

I have a 99 impreza outback sport 2.2L I can not fill gas in the vehicle it seems as though there is too much pressure in the tank and will not let any gas in. I have changed fuel filter and plugs and still get hesitation and can't fill gas. I also disconnected vent lines at filler pipe and this hasn't helped either. I am bout to drop tank and check the pressure valve. Any help would be greatly appreciated!!