Just purchased a used 2014 MDX. Have had for about one week. Our second MDX and third Acura. Did my research prior to and wanted the 14 because of the consistent reports of people getting 28 mpg highway. I do mostly highway driving (like 90-95%). In the past week, the highest mpg I have obtained is 22.2.....not happy. Fuled up with 93, no cargo racks or heavy equipment....any thoughts what I can do to improve over time?