[riva2model64]

I'm rather new to hypermiling, but what you say makes sense to me as well. I feel like if one truly wanted to know and had the equipment and methodology, they would have to know the gph of their engine in neutral. The only thing slowing down the car in this case is tire rolling resistance which is pretty negligible, and air resistance which is negligible at lower speeds.

When coasting in gear with the injectors off, I don't think it uses any fuel, however you lose speed due to the added drag of the engine being connected to the drive wheels.

Therefore, without recording any test data, I hypothesize that coasting to a red light or stop sign is far more efficient while coasting in gear vs. coasting in neutral.

I also hypothesize that given a situation where one will coast, then step on the gas again, coasting in neutral may potentially be more fuel efficient than coasting in gear because one will have to accelerate less due to a lower loss in MPH coasting in neutral. Though, without knowing the numbers, either form of coasting may be more efficient depending on the situation. One would also need to know when the ECU turns off the fuel injectors.