Just some info in case anyone is interested. The car is a 2010 Cobalt XFE without air conditioning. Calculated average over one year of driving was 35.2 MPG over 13,760 miles. On board computer showed 38.3 MPG so on my car there is a 3 MPG error in the computer. Most of my driving is commuting 22 miles each way on mostly county roads with 45-55 mph speed limits. A fair number of stop lights and a bit of traffic to deal with. The computer showed 36 MPH average speed for the year. I try to drive for maximum fuel mileage without holding up traffic. I'm in Minnesota so cold temperatures and snow tires reduced mileage in the winter. Roughly the same or a bit better mileage then the Ford Escorts I was driving before. Cobalt has quite a bit more horsepower though.