"The cars aren't going very far. I guess there's some up the street. They are all over the place," said George Aball, one of the affected customers.
Cars that are designed to take unleaded gas will stall with diesel in their systems.
The Thrifty parking lot was clogged with dead cars Wednesday. Many of the vehicle owners said the driver of a fuel tanker made the really expensive delivery mistake.
"I walked over to the tanker over there and I asked the guy, 'Hey, what's going on?'" He said, 'I accidentally put diesel fuel in the regular drums,'" said Dennis Kirwan.
The store clerk at the Thrifty store wouldn't confirm the claims and referred to the tanker truck driver for answers. The drivers had no comment.
One customer said she tried to get her stalled car fixed but no one would step up. The gas station told her to talk to the tanker company, but the tanker company told her to fix it herself and seek reimbursements later.
"I'm paycheck to paycheck, I don't even have a credit card to put it on there to get reimbursed," said Renee Ammann.
Kirwan said while people were still filling up with diesel, Thrifty employees said nothing to the customers. They just taped small signs on all the pumps and went back inside.
"The employees are in there hiding out, the owner's hiding out and I'm out here telling people, 'Don't put that gas in your car.' And then I stopped and I thought about it and said, 'Wait a minute, why am I the one telling people not to put fuel in their car because it's diesel?'" said Kirwan.
Customers said that when they went inside to talk to a Thrifty employee, they wouldn't even refund the money for the diesel that was put in their tanks.
Thrifty is run by Arco, which is owned by British Petroleum. Calls to BP offices for comment were not returned.