I have a 2002 saturn sl2 and i have a problem with the gas tank. since its been cold (i'm in minnesota) the tank is full of air. everytime i pump gas it stops every 50 cents or so and if i pull out the nozzle out slightly i can hear air hissing out. if i wait until the hissing quiets i'm able to put in a few dollars but if i keep on pumping without waiting it will spit gas out. how can this be fixed? thanks