This American car got 40 mpg on the highway. A 2009 Chevrolet Cobalt XFE equipped with a manual transmission, 2.2L naturally aspirated 4 cylinder engine, manual windows and manual everything. This car was low cost through and through, but it hit the magic number of 40 mpg. How did GM do it? Tall transmission gearing, special engine software, small engine, light weight and special hard tires to decrease rolling resistance did the trick. This car was almost as fuel efficient as a Toyota Prius at the time at a much cheaper price, but I don't think anyone knew about it.
Another hidden gem of knowledge about the Chevrolet Cobalt models with a 2.2L engine, manufactured from 2005 to 2010, is they all had really good highway fuel economy. A person online said their 2006 2 door Cobalt with 205,000 miles still gets 37 mpg on the highway. His car was just like the XFE model, but with a 4 speed automatic transmission and without the special tires or tweeked software. Which leads to this question: How much did the special hard tires help the XFE Cobalt reach the magic number of 40 mpg? I don't know the answer because these special tires are no longer manufactured and I don't have access to a Cobalt XFE. Anyone who took care of their 2009 Cobalt changed the tires years ago. Tires degrade over time, so tire life is around 5 years. If you manage to find one with or without the special tires it probably gets less than 40 mpg on the highway, but it's still a very fuel efficient car.
