Ford says that its C-Max Hybrid has been stealing sales from Toyota's Prius -- but reviewers say that the C-Max's mileage doesn't meet Ford's claims. Photo credit: Ford

Ford (NYSE:F) has had tremendous success with its latest lineup of hybrids. The hybrid Ford C-Max and hybrid versions of the Ford Fusion and Lincoln MKZ have rocketed up the sales charts -- and put a big dent in Toyota's (NYSE:TM) share of the U.S. market for hybrid cars.

Ford's hybrids get great reviews, but there's a catch: Most folks don't get the 47 miles per gallon that Ford claims. Now, Ford's trying something new: a software upgrade that could help improve its hybrids' fuel economy.

In this video, contributor John Rosevear looks at what Ford is hoping to accomplish with this latest move -- and at whether it's a move that might be imitated by others, starting with Toyota.