The mom said the dealership told her it could cost $800 out of pocket to drain her tank.

MANCHESTER, Mo. — Natalie Lutkewitte often buys gas at Costco Gasoline on Highlands Boulevard Drive in Manchester.

On Friday morning, the Eureka mom said she filled up her 2017 Chevrolet Suburban at the west St. Louis County gas station, and within minutes of leaving, she got big surprise.

"My whole suburban just started shaking, making this loud noise and would not move at all while I was pushing the gas pedal.... My check engine light came on and I was in the fast lane. I didn't want to get hit. I didn't want to get rear-ended," she said. "I just think it's unheard of. I was stressed and it was scary. I'm so glad that I didn't have my four kids with me at the time."

The startled driver immediately drove to her dealer and was told she did not have regular gas in her tank, but E-85, a blend of ethanol.

What's more, she says the dealership told her it could cost $800 out of pocket to drain her tank.

"I have four kids. I don't have $800 to spare. I was calling six different gas stations when I finally narrowed it down to Costco, because no one sells E-85. It's just not out there," Lutkewitte said. "When I called the store, the manager immediately stopped me when I was telling her what happened and said I was not the first person she talked to about the gas mix up."

A manager at the Costco Gas Station told 5 on Your Side they have received complaints from customers. He would not say how many, but said the station is "working with each of the customers to fix any issues with their vehicles."

A 5 On Your Side crew saw pieces of papers taped to every pump on Saturday that read: "We are having issues with our regular gas. We have reduced the price of premium to match the regular gas."

"I need a big car and I just want my car back," Lutkewitte said. "I am right now driving a rental car and that's costing me $70 a day. I am confident Costco will work this out."

A letter from Costco sent Monday said it would pay for any fuel system diagnostics, repairs or related expenses, including rental cars. The full letter is as follows:

Dear Members,

Our records show that you may have purchased regular unleaded gasoline on Friday, October 11, 2019 at the Manchester Costco Wholesale Gas Station location at 301 Highlands Blvd Drive, Manchester, MO.

A small percentage of members who bought regular unleaded gas from our Manchester gas station that day have reported problems with their vehicles, including sputtering, loss of power, or difficulty starting their car.

The impact to your vehicle should be minimal; however, if you have any concerns with your vehicle and would like your preferred mechanic to provide a diagnostic check, feel free to do so. Costco will reimburse expenses associated with any fuel system diagnostics, repairs, or related expenses such as a rental car.

To receive reimbursement for your repair expense due to regular gasoline purchased at the above location within the listed time frame, please call or visit the Membership desk at the Manchester Costco (636) 686-7400.

The fuel in our regular unleaded tanks has been completely replaced, so you can be confident in buying fuel there going forward.

We apologize for any inconvenience this issue may have caused you.

Thank you for your continued trust in Costco Wholesale.