Apparently when coasting in gear or engine braking (on a standard), the engine cuts off fuel altogether while decelerating until it hits a predetermined limit. When coasting in neutral the engine still uses fuel but at a low rate(idle).
I'll have to experiment with this and compare a downhill glide in neutral vs. say 5th gear.
|Mode||Sustain Speed||Fuel Ef.||Safety|
|Coasting in Gear||worst||best||best|
|Coasting in Neutral||good||worst||good|
|Coasting Engine Off||best||best||worst|