I just got home from driving from Lafayette, LA to Hoover(Birmingham), AL. My 2008 Malibu 4-cylinder/4-spd auto got 32.6 MPG and that was with the cruise control set at 76MPH almost the whole way, it was a 440 mile trip. The car had me my wife, our 2 dogs and trunk full of stuff too. I ran 93 octane in it the whole trip and I have put a K&N airfilter in it, not sure it that helped any. Just wanted to share, thought that was awesome.
I've gotten 36 on my 09 2.4L starting from OC to Queen Creek Az. Cruised at 76 starting at banning till queen creek. Next trip i'll snap a photo of my MPG on my BU.