Published: Dec 12, 2012 5:52 PM EST
Updated: Dec 12, 2012 6:12 PM EST

FORT MYERS, Fla. (Consumer Reports) - An American automaker is responding to claims its mileage estimates on two popular models may be overestimated.

Consumer Reports says its real-world tests of the redesigned 2013 Ford Fusion and Ford C-Max found the cars averaged less than the advertised miles per gallon.

For example, Ford says it's new Fusion can achieve 47 MPG in the city, on the highway, and combined.

Although testers found the Fusion and C-Max both have good gas mileage, experts say the results were nowhere close to Ford's claims.

"We measured 35 miles per gallon in city driving, 41 highway and 39 overall," said Consumer Reports' Rik Paul. "That's good fuel economy, but it's far short of 47 MPG that Ford is claiming."

Ford disagrees, and says it has heard from satisfied customers who have obtained 47 MPG or better.  Ford officials also say your mileage may vary depending on driving habits and road conditions.

Ford is not alone.  An estimated 900,000 Hyundai and Kia drivers recently learned the automakers may have overestimated mileage on their cars.  As a result, some Hyundai and Kia drivers are eligible for gas rebates.  Individually, the rebates will likely be less than $100, but collectively they would cost the automakers tens of millions of dollars.