I've driven between Ohio and Wisconsin many times in my Lincoln Mark VIII (4.6 DOHC 280hp V8). I consistently got 26.5 mpg, averaging 75-80 mph. Even though it was a powerful engine moving a heavy car, I got pretty good mileage because it could get up to speed quickly, and once it was there, it didn't have to work hard at all to maintain it.
Another time I took a 2005 rental Taurus (OHV 3.0 V6, ~150hp) on the same trip. It was straining to maintain the same speeds, and I had to keep the gas pedal mashed to the floor when leaving onramps and toll booths to get somewhat decent acceleration. As a result I got 20.5 mpg.
Same thing with my mom's '98 Kia (ATX 1.8l 125hp 4-cyl). When I'd drive it around town, it would get a whopping 17 mpg because I was constantly flooring it.
With my Contour, it's capable of accelerating to my liking without being overworked.. But it feels and sounds so nice that I end up flooring it and shifting at redline all the time anyway.
Those of us with lead foots don't really benefit from driving underpowered cars!
