In a recent issue of Car and Driver, they reviewed gas mileage myths and said something I have a hard time believing:
When Coasting to a Stop, do Not Shift Into Neutral
"We went in search of an expert opinion on this one. According to Paul Williamsen, the product education manager at Toyota, “All contemporary Toyota and Lexus vehicles (and every other car built since the 1990s that I’ve looked at) can detect the condition when engine revs are higher than idle with a fully closed throttle: Under these conditions, all current to the fuel injectors is stopped, and no fuel is injected.” That means if your foot is off the gas while the car’s in gear, you’re not using any fuel.
Tom Read, GM’s powertrain spokesman, agrees: “Shifting into neutral in an automatic will cancel fuel cutoff. Thus, it is better to remain in gear and let the drive wheels pull the engine airflow down to where fuel cutoff can be enabled or where fuel flow is minimized."
from:
http://www.caranddriver.com/features/08 ... pg-feature
Does anyone believe this is true for our vans? My scanguage might show an instantaneous mpg of ~35 coasting down a long straight hill, but if I shift to neutral it jumps up to 99. Seems the Scanguage thinks I am using less fuel in neutral. Going through the mountains, I am sometimes tempted to use this technique during the descent - especially since otherwise my cruise control abruptly/violently downshifts as my coasting speed increases. Does anyone know if this "Car and Driver" advice is correct?
Thx,
-JR
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