2006 Ford F-250 Fuel filling

Up until 2 months ago you could insert the gas pump nozzel and set to fill and it would fill right up and stop
Now it will only take fuel very slowly and even then will sudenly trip the nozzel off and shoot out a big burst of air and fuel I ran an inspection camera down the fill pipe and it looks good. Also I tried to blow air down the vent tube but I don't know if I actually got any air in there as it is hard to access