I'm not sure I agree. the pump is supposed to shut off because of a surge of pressure at the pump nozzle. Seems to me if you built a bigger vent it might make the problem worse.???
The problem I've experienced (also on my Ford Ranger) is that some pumps have the pressure cranked way up, and when they shut off, they simply belch. I have one or two "unfavorite" stations here in town I just never go to anymore.
