Super-Stormtrooper07

Actually in neutral "gliding" does use pretty much gas under those circumstances. After your engine is warmed up, and your out somewhere say at a stop light, put your car in neutral and see what your scan-gauge says- it wont be pretty

Its best to keep it in gear, and take your foot off the gas when ever possible to save gas (coming up to a stop sign, stop light, as soon as turning off on a highway off-ramp, going downhill- have momentum pull you down hill, etc.). Also, reading traffic as far ahead as possible also does wonders.

drwoodwind

Scangauge says:

about .15 gallons per hour engine idle (at speed or stopped)
That's enough to drop the trip average mpg a tenth every 5 seconds on a 10-20 mile trip...
about .20 gallons per hour idle in drive
(add .05 if lights are on)
about 1.0 gallons per hour gets 50+mpgs at speed

I haven't stomped on it to watch, but if I feel acceleration, it's usually above 1.6 - 2 gallons per hour

I can glide a lot longer in neutral, getting 150-300 mpgs, gliding in gear has only been useful if I've got to stop soon, or on exit ramps, where I need to slow down anyway.

(just finished a 50+mpg 16 mile trip between appts. - mix of heavy traffic hwy and side streets...)