Some other techniques I found on today's long 500-mile drive (check my gaslog for the big jump upwards)

When going downhill, do engine-on coasting. However, if going downhill over the speed limit, or there are sharp bends coming up, go back to drive, and try to get it to go into fuel-cut mode (done on my car be putting it in gear, accelerating slightly to engage lockup, then letting go (this only works when I have disconnected the lock-up control lead).

If you have lock-up that disengages at 80km/h (50mph), it may be that your most efficient speed is 51mph, but there is another efficiency peak when the torque convertor is slipping. On my car that was at about 35mph. So, I would do up-hill stretches at high-throttle load (just before enrichment), but once the car slowed down too much, I would go into neutral until about 35mph, then back into gear and would continue the up-hill at 35mph.

Finally, engine-on pulse-and-glide is great for mild downhill stretches where the car slows down but the 100-80km/h (62-50mph) stretch is prolonged by the slight downhill grade. (note you need to go into neutral when on the glide for this to work).

Keep it in neutral
 

One more - Neutral at stoplights. Many people with automatics forget this one. Note my MPG % above EPA and you'll see it does help.

Neutral
 

Use neutral as much as possable, stop-lights, down hills and prior to stops. Use the big gear. 28 city 35 highway 99 passat epa 21/31

When you're not interested in reducing speed, neutral makes sense because it won't drag your speed down. When you want to reduce speed, use enough engine braking to trigger DFCO (if your car does DFCO).

It's commonly thought that higher RPM == more fuel usage, but does it if you're not stepping on the gas and the road is turning the engine (but, for whatever reason, not in DFCO)? Would the engine need to inject the same volume of fuel more often for more RPM, or it can it inject less fuel? Can anyone answer that definitively? I will when I eventually get a ScanGauge.

On my auto, idle is 750rpm, and fuel cutoff works above 2000rpm. Therefore, if I am driving with the engine at 1800rpm, it makes sense to pulse, and then glide in idle. Otherwise it injects lots of fuel even if it could have been in cut-off mode.

More modern cars have much better cut-off modes, however. Or at least they should! (The Toyota Avensis D4-D (diesel) has cutoff at any speed above idle :)

Wow, I must admit, some of this is hard to follow. Can anyone tell me what is the safest way to come out of neutral when I need to speed up?

What I have been doing is going into neutral up even the smallest road hills, then mildly accelerating downhill till I hit level or get done accelerating, then putting the car into neutral. My rpms are always at 9-1.1k when moving in neutral(750 idling).

So if I say... coast in neutral all the way over a hill, then mildly accelerate down, cut it to neutral then coast out till I am going about 5-10 mph less than the speed limit, should I rev my engine a little before putting my trans back into drive? I have recently started doing this, and it is the smoothest way to go back into drive while moving. Help?

I'm not sure about your Volvo, but in every GM I've ever owned (and probably some Fords I drove a lot) I never had to think about it, I just go from N to D without touching the gas pedal until D is fully engaged.

I run aftermarket rims and tires, have an auto tranny and a turbocharger. I do a couple things to help.

1. Reinstalled boost guage. I used to use it for performance, now I use it to stay in vacuum and make sure Im not in boost.

2. Feather the throttle to keep it under 2200rpms or so. I have "autostick" but I find if the RPMs get too high, I let off the throttle a little bit to get the transmission to shift then I speed up again. I only do this through the first 3 gears - 4th is OD for me and a weak point for the 41TE.

3. Speed up slowly, maintain speed limit or below. Duh

4. Try not to use either pedal. You shouldnt need to brake hard or speed up hard if youre in tune with traffic.

I do pretty well all things considering. We also have a 2008 Yaris that gets 40mpg with barely trying so thats the mpg car. Picked it up for 11k OTD with 1,400 barely used miles from a Chrysler dealership. Bare bones with 5 speed and the convenience package.

On my Odyssey, the transmission jolts a bit when going back into drive above about 40mph. In that case, I blip the throttle to about 2000 rpm to rev-match first. A little high seems to be smoother than a little low.

is it bad to turn off you car when your able to glide a good distance? because I do that. I have a 93 saturn sc2 auto. I have got several places on my usual routes that i can put my car into neutral, turn the car off and glide, you loose power steering, but 30+ you don't need it, and power brakes after a few hits. There is one area that i think i glide for nearly a quarter mile before the stop sign comes. i have to look at my tripmeter next time i go there. i only do this if i'm going to be coming to a complete stop, if something happens, suppose the light turns green before my spot, i just turn on the engine, wait for it to stablize and tap the accelerator to get the rpms up if need be, put it into drive and go.