I have a 2004 chevy blazer 2wd, can't pump gas into blazer.

I have a 2004 S10 Blazer, 4WD, Automatic At about 80K miles I had the same problem; filling the 19.1 gal gas tank was difficult. The problem was with the rubber connecting hose between the metal fill pipe (gas cap end) and the gas tank. After this short connector, rubber hose was replaced the problem was resolved. Good luck with yours.

What happened to that hose that it had to be replaced?.. What was inside it to stop tank venting?? .. Reason I ask is I have fixed a 'BUNCH' of these at the shop but NEVER had a problem with that vent hose!!