With a White House mandate that better fuel economy become a priority for auto makers, the Environmental Protection Agency is hounding Ford to fix the inaccuracies in the fuel-economy estimates for six of its vehicles.

And there's a time limit of 15 days attached as well.

The vehicles where Ford needs to address its estimates are the Fiesta (Hybrid and Energi versions), the Fusion, the C-Max Hybrid and Energi, as well as the Lincoln MKZ Hybrid.

"This issue highlights the need for continued strong oversight of the fuel economy labeling program," said Chris Grundler, the EPA's Office of Transportation and Air Quality director. "Consumers need to trust that fuel economy window stickers are giving consumers reliable and fair estimates of real world fuel economy."

Ford has assured the EPA it has "identified an error" during a recent internal investigation of the issues in the vehicles being questions and is now working with the EPA to lower the fuel-economy estimates to the correct levels.

President Barack Obama's plan to reduce the gases blamed for global warming recently turned even more of its attention on the auto industry, focusing on improving fuel economy in U.S. vehicles. The president's goal with the plan is to double the average fuel economy of vehicles to 45 mpg (19 kpl) by 2025.

One way the auto industry plans to meet this goal is by building lighter vehicles. Thus while all the new hybrids and electric cars continue to steal the headlines, when it comes to better fuel-economy in the near future, many experts feel the move to building cars with lighter materials is where the real action will occur.

According to the EPA standards plan, by 2025, light-duty vehicles will be expected to release emissions equivalent to a 54.5 miles-per-gallon rating.

But Michael Sivak, a research professor at the University of Michigan's Transportation Research Institute, claims the progress the auto industry is making in the past few years is on target, even suggesting a touch above. "We're slightly above where we need to be," he claims. Sivak added he expects the average mileage of new vehicles sold in 2014 will hit 26 some time this year.

Ford CEO Alan Mulally issued a statement of apology over the issue.

"Ford is absolutely committed to delivering top fuel economy and accurate information. We apologize to our customers and will provide goodwill payments to affected owners. We also are taking steps to improve our processes and prevent issues like this from happening again."