Unless I'm missing something, what you described is called "idle flare-up" and it is what all fuel injected engines are supposed to do at start-up. 2200 rpm seems a little high, but the fact it comes back down right away proves there's no vacuum leak, and it proves the idle air control valve is working. It will increase engine speed slightly when you shift into gear or turn on the air conditioning to make up for the added load on the engine.
You made a comment about idling rough but didn't elaborate on that. You don't suppose a misfire would affect idle speed, do you? The Engine Computer has enough control with the idle air control valve to overcome a misfiring cylinder, but that changes the characteristics of how that system will control idle speed and respond to needed adjustments as the engine is running.
Monday, January 13th, 2014 AT 5:21 PM