We had the mini worked on at a shop here in town and they did a great job but a couple of hours after we picked the car up the idle would bounce around and nearly cutoff without setting a code. I was doing some research on symptoms and repairs, I thought it might either need this part or that part replaced. Tonight I went out to install the blanking caps to delete the pcv intake tube that connects from the throttle body to the valve cover. Got everything reassembled and low n behold... No more idle issues yet!!!

 

Yeah, that PCV tube to the intake manifold is the worst. Not sure I would blank it off, but at least replace it with proper hoses and a catch can.