That's pretty much what I do. I average about 240 miles on 10-11 gallons of gas combined. If it were strictly hwy, I'd get at least 300 miles on a tank.

If I got any worse than that, I would check the obvious tire pressure, plugs, fluid. If all is okay, I'd probably plug up my flashpro and monitor the readings but have yet to get that far. It's usually tire pressure for me.