P0440 Code

I have a 1997 Pontiac Grand Am. I have been getting alot of pressure and hissing coming out of my gas tank when removing the gas cap. It is such that it would almost blow out of my hand if I unscrewed it fast. Also, check engine light is on and took it to Advance Auto Parts for a scan and it is bringing up Code P0440, EVAP Emission Control system Malfunction. Do you have any suggestions?

There's not much to the EVAP system. You've either got a bad fuel cap or a plugged line going to the evap purge solenoid. Everything else that'll set this code wouldn't really cause the excessive pressure in the tank.

At least, so goes in my mind. Someone else may be able to point you better than me.

Thanx cadgear. I will definately check that out.