Was a beautiful day out... 63F. I was about 50 miles in to my 80 mile trip home. I drive the same way on the highway all the time. 65 mph, cruise control the whole way.. right lane. I have a 2011 Cruze, Automatic transmisison, same 1.4T as the Sonic. It's rated at 36 MPG. It took over 10,000 miles to reach 40+ MPG at this speed. When I first got it in Augist, it was a good 5 MPG lower. Break in counts for something...