refueling problem

NEED SOME HELP WITH THIS PLEASE .I HAVE A 2001 JIMMY AND HAVING FILLING PROBLEMS . IT SEEMS LIKE THE TANK IS FULL . IS MY VENT OR EVAP SYSTEM THE PROBLEM:banghead: :rofl: .IT TAKES ME 20 MIN TO PUT TWENTY DOLLAERS IN MY TANK. SOME FEED BACK PLEASE.
THANKS svp1949