Idle speed hunting is common after a TB service.
An ecu reset by taking battery terminals off usually does the trick.
But it takes a few days for the ecu to recalibrate itself because it needs cold-hot-cold cycles to determine idle speed, which it does every time the car gets to operating temps from a cold start. If you didn't take off any electrical connectors/sensors or fiddle around with the throttle plate manually, then in my experience this is the most likely situation.
Give it a couple days to relearn. I usually do a cold start and let the engine warm-up itself till the radiator fan comes on.