Thanks Sean, That explanation of open v. closed loop makes sense. Has anyone done any research on whether the OBD-II learning affects our mileage? If hypermilers train their OBD-II brains to expect us to run in open loop the majority of the time, does that affect the transitioning to closed loop? I did take your FAS key off advice, and let my idle speed drop to 1000 rpm before keying off. After I pulse, my rpms plateau at 1300 rpm for a few seconds, then drop to 1000 rpm. That's when I key it off. Idle is at 700 rpm, but I haven't waited for the engine to drop that low. I think I'd be ready for another pulse by then. I can't wait to see how my wife's AT Elantra handles our upcoming Christmas trip. It got 38.5 or 38.6 mpg over 800 miles on cruise control at 55 mph to my mom's this Fall. I'm hoping for about a 5-6 mpg improvement this trip, hypermiling. There doesn't seem to be much I can do with it other than substitute NICE-on for FAS, and DWL and DWB. P&G for 400 miles each way seems like a lot of work, and potentially hazardous with the high-volume Christmas traffic. I see about 8-10 mpg improvement in my MT car hypermiling over cruise control, so 5-6 mpg seems doable with an AT auto. I like your hypermiling to chess/billiards analogy. I'm a decent chess player, and have played enough billiards to know what to do. A college friend held the student union title for several of the table games. He could play opposite-handed, and beat me. I learned a lot from him.