Reporting gas mileage is a tricky subject for automakers. Naturally, you want your car to be seen in its best light. You test it according to regulations, and publish what you find.

Sometimes, it can go wrong. Hyundai and Kia found this out the hard way recently. Now, Hyundai's done it again--but caught it quickly this time around.

Launching the car in its home market of South Korea, writes Associated Press, Hyundai handed out publicity materials with an inaccurate, overstated gas mileage figure.

In internal testing, the car is said to reach 28.4 mpg--but Hyundai erroneously published a figure of 29.6 mpg.

This time around, Hyundai managed to catch its mistake quickly, announcing its mistake and correcting the error. But the error dredges up unpleasant memories for Hyundai, who along with partner Kia overstated gas mileage on 900,000 vehicles sold in the U.S.

Thirteen different models from the 2011-2013 model years were affected, and some vehicles were found to have window stickers up to 6 mpg more than official testing could return.

The companies corrected window stickers on all 13 models, and announced that $395 million has been set aside to reimburse affected owners.

It's consumer confidence that may really affect Hyundai and Kia though, with 900,000 North American customers now driving around in vehicles less efficient than originally advertised. The debacle could also affect the brands' previous reputation as makers of fuel-efficient vehicles.

Ford too has been reprimanded for overstated mileage in recent years, its hybrid models unable to meet the stated fuel economy in real-world driving.

As automakers strive towards greater fuel economy--and buyers place more importance in such factors--we've probably not seen the last of inaccurately-reported gas mileage.


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