mal_TX

For anyone else who actually wants to read my posts, here are some examples of what I'm talking about regarding closed throttle fuel cut-off:

http://youronlinemechanic.com/2007/1...ation-control/
"Fuel cut-off control

The fuel cut-off control stops the fuel injection when the engine speed is higher than a determined speed and the throttle valve is closed. Fuel injection will resume when the engine speed slows to a determined speed or the throttle valve is opened. The fuel cut-off engine speed and fuel injection resumption engine speed will increase when the coolant temperature is low. In addition, the fuel cut-off engine speed and fuel injection resumption engine speed are increased when the air conditioner switch is on to prevent the engine speed from falling and an engine from stalling. There are also some engine models in which these engine speeds drop during braking (i.e., when the stop light switch is on)."

http://en.wikipedia.org/wiki/Trionic_T5.5
"Fuel cut

With fully closed throttle and engine RPM over 1900 RPM and with third, fourth and fifth gear fuel cut will occur after a small delay (some second). On automobiles with automatic transmission fuel cut are active in all stages. The injectors are reactivated when the RPM hits 1400 RPM."

The engine turning is what drives all the systems in the car, via the belts that turn things like the alternator and the water pump, etc. As long as the car is in gear and moving above a certain speed, the wheels turning will turn the engine (afterall, it is all connected). When the computer sees the revs drop too low, it will start injecting fuel again to prevent the engine from dying.

I guess this has little to do with the OP's question.