According to an article in the Chicago Sun Times, a Lockport couple is part of a new group of consumers suing Korean carmaker Hyundai over exaggerated fuel economy claims connected to more than 600,000 vehicles. Sarah and James Kundrat, of Lockport, filed the class-action lawsuit in federal court Monday along with Schiller Park resident James Gudgalis.

Nilufar Rezai, who bought a 2013 Santa Fe Sport from a Chicago dealership in October, filed a similar federal class-action suit Nov. 14, also taking aim at the inflated gas mileage claims.

On Nov. 2, Hyundai and Kia announced a “procedural error” at the companies’ joint testing operations in Korea led to cars being labeled with fuel economy ratings an average of 3 percent higher than they actually performed, the carmaker said in a release.

The error affected more than 600,000 Hyundai vehicles in the 2011 to 2013 model year in the Elantra, Sonata, Accent, Tuscon, Santa Fe, Azera, Genesis and Veloster lines.

The plaintiffs in Monday’s lawsuit all claim they bought their Hyundai Elantra vehicles in part because of advertisements touting the model’s 40-mpg highway rating. Their cars did not achieve that mileage in the real world, they claim.

The carmaker has established a reimbursement program, issuing customers a debit card to compensate them for additional fuel costs as long as they own the car, plus an extra 15 percent, according to Hyundai’s website.

Kia has also established a reimbursement program for 300,000 owners who bought certain Optima, Rio, Sorento, Soul and Sportage models in the 2011 to 2013 model years.

Both carmakers say they are relabeling all vehicles still at dealerships and correcting errors in its testing process that led to the inflated ratings.

“We think our reimbursement program provides the best, quickest, and most customer-focused remedy,” Hyundai spokesman Christopher Hosford said in response to the November lawsuit.

“Owners have responded very favorably to the plan. Our priority is to make this right for our owners, and that’s precisely what this program does.”