Chevrolet Repair: 98 Chevy Malibu 3.1L Takes Gas VERY Slowly!!!, chevy malibu, vent lines

Question
I have had my 98 Malibu 3.1L for a little over 2 years. I've had this problem twice. The first time, it seemed to correct itself. But, now it's doing it again...
When I try to pump gas, I have to do it VERY slowly because the gas tries to spew back out. I know there are vents and hoses that are supposed to regulate the air in the tank. The gas pump thinks the fuel tank is full and tries to shut off.
My husband has been driving it to work sometimes to a coal mine where it gets REALLY muddy. Is there a vent on the outside of the car that could get stopped up by this mud? If so, where would it be located?? The car only seems to have this fuel problem after my husband drives it to work for a period of time.

Answer
Hi Sarah... yes there are vents in the system...one goes to charcoal cannister under the hood. check to see if it is dirty. there is a filter in it that can be changed... a local parts store will be able to get for you. i can't send diagrams over this link but if you go to local GM dealer he can print you one of the system...also check for collasped vent lines.. there are three lines out of the tank... one is fuel to engine one is return fuel and the third is vent....hope this helps