gas shoots out when filling

Just sounds like your putting the nozzle too far into the filler neck. Try backing it out a bit and let any air pressure building up in the tank escape. The very reason why they put warning labels on the pumps telling you not to smoke while filling, it is because of the air that is escaping. It is part flammable fumes and part air that needs to escape the tank. It spits because it is building a really big air bubble, but has nowhere to go because the filler neck is getting sealed off by the nozzle. Sorry for the long explanation and I hope this helps.