So several days ago, at Ford Motor Co.'s invitation, I went to visit John Davis, Ford's chief engineer for the C-Max, Focus and Fiesta, to see what I was doing wrong and why I was only getting about three-quarters of my car's promised 47 mpg.
Davis rode along with me in my C-Max, passing along tips for the best ways to accelerate, the optimum method for braking and a pulse-and-glide system for improving cruising efficiency.
After reviewing the onboard displays that tracked my precoached driving -- all of which were within striking distance of peak efficiency -- Davis decided that my biggest problem is one of the most common: speed.
More than 96 miles of my 120-mile daily commute is on I-75 -- a six-lane interstate in southeast Michigan with a legal speed limit of 70 mph and traffic that moves significantly faster. The C-Max's electric drive is of little use over 62 mph, leaving the heavy work instead to the car's 2.0-liter I-4 gasoline-burning engine.
Davis said that efficiency will rise when my vehicle is broken in -- about 1 or 2 percent better mileage. He suggested that my best bet to improve my overall mpg is to use the C-Max's cruise control on the highway as much as possible and to drive more efficiently elsewhere. The coaching has already changed some of my driving habits: I now accelerate more evenly and use the cruise control more.
The C-Max has several information screens that allow the driver to see when the car is being pushed by its electric motor and when it's operating with its traditional drivetrain. Using these monitors to keep the car under electric operation for as long as possible will raise my mpg, as will long, slow extended braking that recaptures energy in the car's regenerative brakes, Davis said.
I've heard from several fellow C-Max owners since I made my purchase. Some, like me, have said that they haven't yet come close to the promised mpg. Others told me that they've exceeded it.
I'm willing to keep trying to reach the promised 47 mpg. But if I never make it? Well, there's always diesel.