Ford: Driving style determines C-Max hybrid's fuel efficiency

It is giving you the same info as the F150. It just happens to a flat 47 for the Fusion. The Prius is 51/49(48?), which isn't much better for how you want to use the numbers. If I could access fueleconomy.gov from here, I think I could find some non hybrids with city and highway ratings nearly as close.

One is a number what you get when driving under EPA city conditions. The other, is for under EPA highway conditions. Know your actual ratio of those two for a trip, and you can figure out what your single number MPG for the trip should be. The fact you got within the two with your F150 Proves the 2008 changes to the EPA test were a big improvement in getting the consumer numbers closer to real world. The new Ford hybrids happen to get the same numbers for both in the tests. Assuming that the results are correct, it isn't a failing on their part with the sticker.

To save typing, I should just started with this. Your complaint that, "No You may get within this range anywhere on the sticker," is unfounded because that is covered by the 'your mileage may vary' warning. Austingreen gets worse than EPA with his Prius. I get better with an HHR. That we both fall outside the EPA doesn't mean the numbers Toyota or GM put on the sticker were wrong. Neither is Ford's(more later). Using digits after the decimel would give you the range you want, but the sticker numbers aren't your real complaint.

One of three things is going on with your new Fusion; the test numbers are wrong, something is wrong with your car, or both are alright and nothing can be done.

Let's starting with the least agreeable. You guessimate that the 18" wheel/tire combo is costing you 3mpg. Some claim that E10, which is common in most areas, will give a 10% hit to fuel economy. The EPA test calls for straight gas. So 3 plus 4.7 is a 7.7mpg reduction. 1.3 can be in the noise to reach to 9mpg loss you are seeing. We need to switch the wheel combos between two Fusions to really know the hit there. I doubt 10% is the real penalty with using E10. It varies with the water content, but you have multiple tanks from various stations to rule out bad fuel.

It is suspicious that a lighter car with lower cD gets the same EPA rating as another. There was once a clause that allowed a manufacturer to use EPA test results for models with the same drive train. Perhaps Ford did that. Doesn't explain your issue, since the Fusion should be the one with the highest numbers of the two hybrids. We'll have to wait for the EPA's own test results.

I think BobWilson and others covered what could possibly be wrong with the car to cause the lowered fuel economy. Hopefully the dealer and Ford find it.