When we reported Wednesday that Hyundai and Kia had misrepresented mileage claims on multiple vehicles, we couldn't help but wonder how they were able to put false numbers on sticker prices that are supposedly reviewed and approved by the EPA.

Are those numbers valid? That’s the question motorists – and regulators – are left wondering in the wake of the revelation, last week, that Hyundai and Kia had inflated their own mileage figures by as much as 6 mpg on 13 separate models. The Environmental Protection Agency is apparently getting ready to review other makers’ mileage claims, the Detroit Bureau reports.

Meanwhile, even numbers that meet government scrutiny are coming under question because of the way the auto industry promotes mileage in advertising.

The EPA, which oversees fuel economy testing and sets rules for how the results may be listed by manufacturers, underscored the significance of the Korean mileage scandal by noting only two other products have been found to use false mileage claims since 2000.

But, has the industry generally lived up to the rules – or have regulators simply been lax in enforcement of guidelines that allow automakers to influence the final figures shown on their so-called Munroney window stickers and used in prime time advertising?

That’s apparently a question the EPA is now asking itself. The agency noted that the audit that snared Hyundai and Kia is part of “an ongoing investigation,” hinting that the figures used by other makers will now face much closer scrutiny.

Even if federal investigators determine the Hyundai / Kia circumstances were unique, and that other makers have played by the rules, the debate over fuel economy will likely continue. For one thing, critics contend the EPA test itself isn’t necessarily a valid reflection of the real world. Indeed, the agency occasionally tweaks the process to make sure it reflects what motorists will actually get. That happened just a few years ago when it became apparent that hybrids were routinely getting excessively high EPA ratings.

Bottom line: consumers need mileage numbers they can trust. If EPA and/or other federal agencies are going to impose testing standards, they need to ensure results and accuracy in what's communicated to the American public too.

Automakers found guilty of using fradulent information should be severely penalized.