Have you noticed sometimes you hit the gas station and you get a pump that sort of stalls for a second when the lever is squeezed? But the money meter starts right away — anywhere from 2 to 6 cents rack up before the gasoline starts gushing. Apparently it's a common, though hard to diagnose and often ignored problem with the "check valve." That's the gizmo that's supposed to make sure gas flows at the same time you start paying.
But even if your gas pump is in full working order, it's allowed to be off as much as $5 for every fill up. Local regulators who test the equipment allow a pump to charge as much as 6 cents more than the gas delivered in a five-gallon test. Regulators try to check out the equipment every six months but some cash-strapped counties don't even meet the one-year requirement in states like New York. The moral of the story? Stay vigilant and keep your eye on that meter.