Hi, my boyfriend and I recently purchased a 2008 Mazda 3 hatchback. It has a 2.3 liter engine. Its gas tank is 14.5 gallons and it is supposed to get 22 mpg in the city and 29 mpg on the highway. The gas mileage seems to be okay in the city but on the highway it seems to go through more gas than it should. We drove to lansing and back which is about 40 miles there and 40 miles back taking the highway all the way there and back. When we got home we had like 2 notches above half a tank. That means it used like 6 gallons of gas when it should have only taken like 4 gallons of gas. Also, when driving on the highway it rides at 3,000 rpms. What could be causing it to use a lot of gas on the highway? Could it just be because it has a smaller engine?