Try different stations, as others have said. When I lived in DC, a lot of gas stations had some sort of vapor recovery thing around the filler nozzle. I'm not sure if they were the cause, but those pumps tended to be hypersensitive and would never let me fill up the tank very quickly. I'd always go to the less environmentally-friendly pumps becuase they'd let me fill up my tank in a reasonable amount of time.
