Hello. I've had my Terrain Diesel for about 3 months now and I have put about 6000 miles on the car. Everything seems to be great except the gas mileage is not what I have expected. I'm averaging a consistent 28mpg combined City/Hwy. My first trip out of town I drove 164 miles and got 30mpg, and made the return trip the same day and still did 30 mpg. I've heard stories of 40 plus MPG! What kind of gas mileage are you experiencing? I would like to know before I take it into the dealer. No code are showing up and seems to run good.