@Bill - I would change out the iac. I have had multiple vehicles where they just start sticking and sometimes its hard to tell. I even had one new one sticky out of the box, so even a new one is no guarantee that it will function correctly.
I’ve had similar issues with thermostats. Every thermostat I’ve bought from and auto parts store was stuck closed or opened too late. After playing that game three or four time I said I will not buy a parts store thermostat again. OEM only.