Well, the symptoms you are describing are actually kinda normal to me. The ECU does increase the idle speed in certain situations to prevent stalling. But it can be more pronounced if your ECU has recently lost power and has to re-learn the idle curves.
It may also be a vacuum leak somewhere that has recently cropped up, and the stepper motor hasn't adjusted to it yet.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.