Woman Goes To Fill Her Gas Tank Up At Costco. Then The Pump Won’t Turn Off: 'Overfilling Can Push Liquid Fuel...'

Costco’s renowned not just for free samples, bottom-barrel food court pricing, and bulk deals, but also for comparatively cheap gas prices. But one member of the popular retailer faced a nightmare pump situation: her fuel pump wouldn’t stop pouring gasoline.

Abby (@abbyjadee), a mother of four, uploaded a short social media clip showcasing the aftermath of her gasoline malfunction. The video begins with an image of the wasted gasoline strewn across the ground. Somberly, she can be heard expounding upon the situation off camera.

“Nothing like filling up your car at Costco and the pump not shutting off,” she says. As she does so, several workers wearing neon yellow safety vests can be seen cleaning up the mess.

Costco May Profit From Surging U.S. Gas Prices In 2026

TheStreet reports that as of May 7, 2026, national gas prices jumped up to $4.55. This is largely affected by the cost of crude oil skyrocketing in the midst of America’s war with Iran. Additionally, controversies around the Strait of Hormuz have been affecting gasoline prices, with Exxon’s CEO saying the full sticker shock of the blockade has yet to be realized, which means consumers may be in for even high fueling costs.

This makes Abby’s incident all the more disheartening, despite Costco’s historically low fuel pricing. The Motley Fool writes that the retail chain’s pump prices usually sell for 20 cents cheaper on average, depending on the region. According to the outlet, these savings may influence drivers to fill up their gas tanks, and while they’re getting gas, they may be prompted to get other shopping done there as well.

“If the Iran War drags on, Costco could attract more new members with its low gas prices and discounted goods and services,” The Fool speculates. Moreover, TheStreet quoted Costco’s CFO Gary Millerchip as stating that “half of members who … shop at the gas station will also cross-shop at the warehouse.”

Will Driving Habits Change?

Furthermore, TheStreet cited surveys where car owners said that they'd be forced to cut back on driving if prices stayed at over $4 per gallon. Fortune added that many Americans are “driving less, canceling vacations and tightening budgets” in order to cope with soaring pump expenditures. For some, driving less is out of the question, which has spurred many in this 2,500-person poll to say that they are actively seeking new employment opportunities. I.e., finding jobs that are closer to their home or remote working opportunities. Additionally, others have stated that they actively plan trips to businesses or areas where they can complete all of their errands in a single journey, rather than hopping all around town to take care of their needs.

How Does A Gas Pump Know When To Stop Pumping?

Reader’s Digest spoke with an analyst from Genuine Parts Company, Jake McKenzie, who broke down the science behind automatic pump shut-off mechanisms. The way fuel pumps are designed relies on the Venturi effect, which is a “drop in pressure as fluid flows through a constricted area of a pipe,” SimScale writes.

McKenzie went on to explain that when you pour gasoline into your car’s tank, air gets displaced. And this displaced air is what’s responsible for keeping a fuel pump valve open and pouring gasoline. Once gasoline reaches the nozzle of the fuel pump, the Venturi effect occurs. “A small suctioning force … switches the valve to the off position,” the Genuine Parts Company rep said.

The Economic Times also echoed this explanation, stating that air flow has more to do with a fuel pump’s ability to know when to stop pouring gasoline. It’s not measuring the amount of gas inside of your ride’s tank but reacting to the displacement of air, which explains why sometimes gas pumps will prematurely shut off and also why these pumps may still be pouring out gas.

Why Would A Fuel Pump Keep Pouring Gas Into A Full Tank?

Overfilling your gas tank is generally a bad idea, so when the pump stops pouring, don’t try to get a little extra. AAA states that “overfilling can push liquid fuel into vapor recovery components where it does not belong.”

Ultimately, this can damage a car’s EVAP system, specifically its charcoal canister, which could be one of the reasons why a fuel pump may keep pouring gasoline despite a car’s tank being full. Folks on this Civic Forum discussed potential issues that they’ve come across with fuel pumps overfilling gasoline. For the most part, various users stated that the issue may be with the gas pump’s mechanism itself. I.e., it has a faulty or clogged nozzle, which prevents the Venturi effect from doing its thing and shutting off the nozzle.

Another user speculates that drivers may not be inserting the fuel pump nozzle all of the way into their vehicle, which could also stop the pump’s auto-close mechanism from engaging.

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And then there was this ‘92 Ford Ranger driver who complained about the same issue, noting that this was a recurring issue with their ride, regardless of the pump and gas station they use. One person noted that the problem may lie in a blocked vent line in the fuel tank itself. Due to it being gunked up, air displacement becomes impossible, which means there’s no Venturi effect and the pump keeps spewing out gasoline.

Motor1 has reached out to Abby via email for further comment. We will update this story if she responds.

 

 

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