Hi RNP, I had read you had no luck changing the IACV but hope it will sort my issue.
I read a few 'new' bits of information trawling through here, I don't have the posts to hand but two new possible things I will research are:
"IACV 'sensor' has a very small amount of adjustment" the post said after adjusting this it solved their idle issues. (I will try to find this post again and link to it, its about three or four pages into this forum's 'faults and fixes' section.
Lastly someone has mentioned a 'idle slider' on the ECU in this thread, I have not heard of this before. Again I will do some research.
I'll be buggered if I'm not going to sort this!