every time I shut the door or the hood the idle fluctuates? Why?

In the shop I would take that information as far as to see if it does it for me, which is all about confirming the symptom as described. Provided I do get it to act up, I'd then start testing for what is changing when the door closes, and some kind of a loose connection would be highly likely. Things like main power or ground connections could do this so measuring for a voltage drop across them or simple wiggle testing would be applicable.