Can't fill gas tank - Pump shuts off

[FieroGT42]

I have a 95 Prizm that I got a few months ago, and it suddenly refuses to take more than a gallon or 2 of gas into the tank at a time. I have to pump really slowly and it it gets increasingly hard to get any in. I can hear gurgling in the filler neck sometimes. Nothing spurts out though.

I tried pulling the hoses from the charcoal vapor canister under the hood when I fill up, but that didn't help at all.

Is there another canister, a valve that suddenly went bad on me, or is there some other type of venting in the neck that's plugged? I'm not sure what to check next. Thanks