When you say overflowed, do you mean that the nozzle clicked off, and not that gasoline poured out of the opening? Did you try a different pump?

I found that not all nozzles are created equal, and some need to be pulled back a little (1/2 inch) to work correctly. I have never gotten used the the California style accordian nozzles that need to be pushed all of the way in before the pump will work.

If you suspect that the vent hose on the car is blocked, that is an entirely different issue. Note: spiders and wasps cannot block the vent tube, the vapors will kill any insects, besides the fact there is no outside access to the vent tube.
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My back feels better when I sit in a Volvo seat