First Hyundai and Kia cut fuel-economy ratings on a dozen models, then Ford on the C-Max.

Then, Ford cut ratings on the C-Max again, along with those of five more models.

Are there more to come?

Industry sources have quietly been discussing in recent weeks that more adjustments to EPA gas-mileage ratings could be coming in the New Year.

DON'T MISS: Ford Cuts Gas Mileage On 6 Models: What You Need To Know, And Open Questions

There's steadily increasing pressure on all automakers to meet corporate average fuel economy (CAFE) standards that rise every year between now and 2025.

And the temptation to cut corners and game the EPA testing cycles is likely getting stronger with each passing year.

John Krafcik, CEO of Hyundai America, with 2012 Hyundai Elantra sedan at Chicago Auto Show, Feb 2012

John Krafcik, CEO of Hyundai America, with 2012 Hyundai Elantra sedan at Chicago Auto Show, Feb 2012

Neither Ford nor Hyundai-Kia admitted to any malicious intent when they had to reduce their EPA ratings and send checks to customers for the extra fuel they'd theoretically had to buy because their new cars didn't live up to the original fuel-efficiency ratings.

A variety of testing and modeling errors by both companies, along with some imprecision in the rules for the "coast-down" portion of the test cycle, were blamed for the erroneously high readings.

ALSO SEE: EPA To Tighten Gas-Mileage Test Rules, Audit More Ratings From Carmakers

Earlier this month, the EPA said it would audit the ratings submitted by carmakers more closely,  and tighten the rules for that testing.

It will also clarify the procedures for the coastdown test, in which carmakers simulate the effect of aerodynamic drag at speed on a car being tested on a stationary dynamometer, or "rolling road."

2014 Ford Fiesta EcoBoost SFE, Catskill Mountains, NY, Jun 2014

2014 Ford Fiesta EcoBoost SFE, Catskill Mountains, NY, Jun 2014

For a good description of how carmakers could game the EPA test cycles--and the effects on car design of rising fuel-economy rules--we recommend an article published last year in Road & Track entitled, "Self-driving tech, standardized tests, and gaming the EPA mileage system."

So back to those industry rumors.

MORE: Hyundai, Kia To Pay $300 Million For Gas-Mileage Testing Errors

We haven't yet heard anything reliable enough to name specific carmakers as the targets of increased EPA auditing.

But let's just say we won't be surprised if we hear of more EPA-ratings rollbacks next year, along with checks for a few hundred dollars sent to car buyers.

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