I recently completed a 5,000 mile cross country trip in a 2014 Fusion Energy Titanium to Florida, Atlanta, Louisville and back to Phoenix. My entire trip average miles per gallon was 41.9 driving mostly on interstate roads with the speed control always set at 70 MPH. Only issue was my speed control would drop out after 4-6 hours of driving and would not reset. After about 30 minutes off time it would usually work again for an hour or two. Can't get it fixed by Ford because they can't replicate it in the shop. Works well around town. Anyway, to my point - during my trip I would see how low I could take the gas gauge then note the gallons during fill up. Several times I took it all the way down to where the white line on the gas gauge would disappear and the yellow low gas light would switch to red. Upon filling, the most the tank would take was 12.7 gallons and amazingly the gallons used indicator was spot on! According to the manual the gas tank capacity is 16.5 gallons. I know there is usually a reserve in the tank, but doesn't 3.8 gallons seem too much? Could it be that the tank is less than 16.5 gallons? Although the gallons used indicator was very accurate, I was afraid to use that information to take the tank down further in the event the tank was less than 16.5 gallons. You may ask what the point is by taking the tank down so low? Well, there is no point, I just wanted to know how low I could go.