JGC

Really? We try this on a super long hill (almost an hour ride) in an Evo VIII and saved over 1/8 of a tank! (Instead of just letting it idle down the hill... the brakes thanks us too) After all it was not injecting any gas at all

But I must admit that I don't know if running the engine like that with out fuel could have long term effects.

GTijoejoe

iTrader: (25)

Negative load is not referring to vacuum. Load being the word to describe the amount of work (general term) required by the engine. For example, less work is required to pull your vehicle on flat ground than up a 45degree incline.
Negative load is when the engine produces no power, no combustion process to produce work. The road load through the drivetrain is turning the engine, compression of the cylinders acts like a compressor pump.

As for long term effects, why would fuel cut be considered a new thing to EFI???
Being purely mechanical where the inertia of the vehicle turns the motor by the drivetrain, as long as everything is properly lubricated, no combustion process will never damage an engine. (does you air compressor pump get damage? )