DETROIT (Reuters) -- Ford Motor Co.'s C-Max and Fusion hybrids fall about 20 percent short of their fuel economy claims, Consumer Reports magazine said on Thursday, after running real-world tests on both models.
The influential magazine said the Fusion hybrid delivered 39 miles per gallon both on the highway and in city driving, while the C-Max hit a combined 37 miles per gallon.
Ford has said both vehicles would produce 47 miles per gallon.
"These two vehicles have the largest discrepancy between our overall mpg results and the estimates published by the EPA that we've seen among any current models," Consumer Reports said. "Among current models, more than 80 percent of the vehicles we've tested are within 2 mpg."
The magazine said the largest discrepancy it had previously seen was 7 and 6 mpg for the Toyota Prius C subcompact and Prius hatchback, respectively.
"While our highway test results almost always meet or exceed the EPA highway numbers, our highway figures for these cars fell far below," the magazine said.
"Most buyers won't get anything near 47 mpg in the real world," Jake Fisher, Consumer Reports' director of auto testing, said on the magazine's blog. "Even though these two Ford hybrids are very efficient, this big discrepancy may leave customers disappointed."
But the company has said it expects to see a wider range for fuel economy on its new generation of hybrids because they are more powerful. Drivers can consume more fuel when they take advantage of the hybrids' higher performance, the company says.
"Early C-Max Hybrid and Fusion Hybrid customers praise the vehicles and report a range of fuel economy figures, including some reports above 47 mpg," Ford told Consumer Reports in a statement. "This reinforces the fact that driving styles, driving conditions, and other factors can cause mileage to vary."
Jim Farley, Ford's sales and marketing chief, told USA Today last week the automaker had no plans to change fuel economy claims on the two models.
Last month, the EPA forced Hyundai and Kia to restate fuel-economy estimates on many models after the companies overstated mpg claims.
The agency investigated the matter after receiving numerous complaints from Hyundai and Kia owners.
Also on Thursday, the EPA and the U.S. Department of Energy released their 2013 fuel economy guide.
The guide includes sections on electric vehicles, hybrids and plug-in hybrids.
The Fusion and C-Max hybrids are listed as getting 47 miles per gallon in the report. The models are the second-best in their class after the 2013 Toyota Prius and Prius c.
There are more than 40 hybrid cars, trucks and SUVs in the 2013 guide, which includes 14 electric vehicles, such as top-rated Toyota's 2013 Scion iQ EV, from 10 manufacturers. The Scion iQ EV gets the equivalent of 121 miles per gallon.
Three plug-in hybrid electric vehicles are rated. Ford's C-Max Energi tops the list with an EPA rating of 100 MPGe.