For now, the suit is limited to one Impala model year.

A new class action lawsuit has been filed against GM in the state of Illinois. It alleges that certain Flex Fuel-equipped vehicles cannot be properly operated while on E85 without the cars sustaining damage. As of now, the only known affected model is the 2016 Chevrolet Impala, claimed by the plaintiff, Michael Fleury.

GM has been using Flex Fuel tech in its vehicles since 2016, and all are marked by a yellow fuel cap, denoting their capability with the text ‘E85/Gasoline.’ For those wishing to read the legalese themselves, filings are available online via the U.S. District Court for the Northern District of Illinois Eastern Division under Michael Fleury vs. General Motors LLC.

2014-2020 Chevrolet Impala Sedan Front View DrivingChevrolet

Fleury states he purchased his Flex Fuel Impala in 2019 because it would have saved him money versus the standard Impala models. When gas prices started to rise, the suit alleges that the gap was up to $2.00 a gallon between pump gas and E85. Of course, as a result, Fleury began putting only E85 into the car regularly. Then, the check engine light came on.

Fleury’s Impala lost power almost immediately afterward. Filings state that Fleury alleges the car couldn’t be safely driven on public roads after that point. In April this year, he brought the car to a local dealer. The car’s fuel pump wasn’t keeping adequate pressure to keep the sedan running. The dealer ruled that the high-pressure fuel pump needed to be replaced, and asked if Fleury was using E85 in his car. He was told, “excessive use of E85, causing a plunger internal to the fuel pump to stick,” and to alternate E85 fillups with gas.

GM issued a service bulletin to dealers providing guidelines on the issue that Fleury encountered, but similar ones were also issued in April 2018 and January 2019. For now, the scope is set to expand beyond just Fleury. The suit currently defines it as follows:

“The class consists of (a) all persons with Illinois addresses, (b) who purchased a GM Flex Fuel vehicle, new or used, (c) on or after a date three years prior to the filing of this action.” It is unclear how many other owners have come forward, if any, as of now. But that certainly doesn’t sound like how ‘Flex Fuel’ cars are supposed to work.