Erratic idle is a common problem with the F22 motor and its generally a sign that the engine is getting too much air from some location. A lot of times that means a vacuum leak. In your case, since you describe the problem as being only when the engine is cold, the most likly candidate is the FITV. Over time the ring in the FITV can come loose and back off which allows too much air to enter the engine. The computer then starts to fight against what it sees as too much air and the result is an erratic idle. Try taking the cap off of your FITV and screwing the ring back down. If that doesn't work it probably needs to be replaced.

I had a similar problem, but the air leak was coming from the idle speed screw backing out too far. Make sure you baseline your idle first to eliminate that as the root cause.