I wouldnt agree with idling an engine to reduce the fuel consumption, because as stated above the turbines use more fuel when at idle!!!
Turbines prefer power and more fuel, as the more heat created from combustion of fuel ensures no surging and the like, i dont really keep the theorectical terms in me head, i just know how they operate! Either way, a turbine is more economic at full torque than idle.. believe it or not!!!
I will try and get the location of this info for you via a link as to ensure its not crap! (For all i know i could of been fed sh1te info!!) Hold on....!