My car is an ancient automatic four-speed, that for financial reasons I can't get rid of. Oh well. Few things I've noticed trying to get the most out of this car. One, with an automatic, there's another major factor affecting the powertrain efficiency: torque converter losses. Basically, torque converters inherently have some slip, meaning the RPM output by the engine is higher than the RPM going into the transmission. This gets progressively worse as RPM goes up. You generally want to keep the car in the bottom of its highest gear ratio to minimize torque converter losses, even if this puts it a good ways below the break-even between air resistance and wheel friction. Two: most any automatic has TWO ratios per gear. Meaning, my four speed has effectively EIGHT gears. Why? Overdrive. There a second sort-of-transmission with two gears, starts in a lower gear but will drop into the higher gear within a certain torque range. Obviously you want to keep this one in the higher gear as much as possible. Coming completely off the gas will cause it to jump back to the lower gear; I found I can keep it locked in by holding the throttle just above five degrees. This tends to prevent deceleration from coasting at lower speeds though, and I'm not sure how much I'm saving anyway. Speaking of, I've found you can "provoke" the transmission. Automatics are very predictable about the conditions in which they'll upshift/downshift; generally, this is a ratio of speed to throttle position, with a lower bound on the speed it'll shift at. As I approach that lower bound while accelerating, I'll dial back the throttle, which will usually significantly reduce or outright kill acceleration, but provoke the transmission into dropping into the next gear much sooner than it normally would. This, of course, means lower RPM, which has all the effects that normally does. At this point, I'll bring the throttle back up and continue accelerating. Of course, the former doesn't apply to "manumatics" with a solenoid-driven clutch instead of a torque converter, and I don't know how CVTs behave. Anything else people have observed? -E- On a side note, I've noticed that P&G simply doesn't work on autos. These almost never can be flat-towed, so you can't kill the engine coasting. The bigger problem, though, is that the ECM wants to keep the engine RPM close to the transmission input RPM, but the torque converter is one-way and won't do this on its own. This means it's CONSTANTLY feeding the engine, and significantly more fuel than it would at idle. This kills the glide.