Gagged At The Gas Pump

ford
gasoline
van
#1

Have a 2001 Ford 350 15 Passenger Wagon

The gas will not go into the tank unless I dribble it in, it takes appprox 1/2 hr to fill. Had the gas tanked pulled, air lines & filler tube checked for blockages, there weren’t any. What could the cause be?

#2

Do you top off the tank or do you stop filling after the first click of the gas pump?