Yes, old thread, but fun to revive. We drove 240 miles in our gasser to a K9 scent work trial last weekend. Horrible head wind. Only managed 22.9 mpg. That was going 75 mph. The return trip was much better. We had a cross wind that wasn't nearly as hard, and I learned something! A woman in an older Chevy Colorado pick-up was playing leap-frog with us (perhaps unintentionally as she had a female passenger and they were yacking), so I decided the last time she passed us to stay behind her no matter her speed variations. Adaptive speed control kept us a safe distance from her. Anyway, instead of driving an almost constant 75mpg, our speed would sometimes drop to 70-72 mph, and our MPG's would go up almost by two. When she sped up to the high 70's, we just stayed back at 75 mph. Eventually she would slow down again and we would catch up, then slow back down to the low 70s. Went on for about an hour before they exited the freeway. Our gas mileage on this return trip had been around 28.4 before this all started. Soon after they got off we picked up heavier traffic as we were approaching the Twin Cities, so speed rarely got up to 75 mph. In the end our average for the trip home was 30.3 mpg.