I don't want to take over your thread but having the same issues as you. Couple weeks ago my 2017 Pioneer 1000 LE randomly stalled out when I started it after already driving it that day and ran fine but sometime that day had a 29-1 MIL but still ran fine and I think it actually went away. The next day it had really high idle and the 29-1 was tough to get home because when shifting idle was so high. So I pulled the IACV and cleaned it and started it before putting air cleaner on. Once I put air cleaner back on I could not get it to start. Thought maybe I didn't have the groove in IACV motor the slot down in the bore and got lucky that the position it was in allowed it to start. It spun and seems to work but read online that it should be replaced instead of cleaned. Nonetheless I bought the new plug and new IACV motor figuring it had to be one of the two from what I read.
Fast forward to today installed the IACV and it started right up but I had the loping idle from ~2300-3000. Decided well it must be the plug so went ahead and changed it and still have the same issue. The IACV motor spins, it starts with and without the IACV plugged in and idles basically the same. The check engine light went away but still have idle issues. I haven't put the air box back on because that is the biggest pain in the whole job.
Now I am at a loss. Does it need to run/be driven to learn new settings? Do I need to reset anything? What is typical idle RPM I don't even remember at this point? Thoughts?