When I turn off the engine since day 1 there is a noise sounds like a servo moving to a default position. Lately, sometimes, it sounds like it does not run the full cycle. Hard to explain, like most of the time the sound might be 1 full second in duration then sometimes maybe only 1/4 second. I am wondering what is it that makes this sound? Is it a spring accuated part returning something to the off position?

 

your fuel pump will make that sound.