If you suspect the pump is the problem, square the nozzle up with a hard flat surface, like the concrete island the pump is sitting on. Firmly tap the nozzle once or twice so the opening in nozzle makes a flush contact with the concrete. This somehow resets something in the dispenser handle. An attendant at a Costco showed me this trick. So far it has never failed.
If the problem is constant and at various pumps, my guess is a restriction of some kind in the filler neck. Could be an Okie Credit Card partially blocking the filler neck.