Quote Originally Posted by aplarsen22 View Post
Reassembled everything, and the idle is perfect. In the end, the issue was the gummed-up IAC, which is partially dependent on the T-junction flow to function. So if you're having this problem, I would go straight to testing and cleaning the IAC, and cleaning the T junction.
Personally, I would start with the T-Junction. It's easier to get at and 9.8 times out of 10 will solve the problem.

On my left hand drive van, it had the high idle issue; cleaned the T-junction and it went away immediately. Not even 6 months later, the high idle came back. Second time around I not only cleaned the T-junction but also installed a filter between the junction and the IAC. The filter should collect any black flakes and prevent the junction from clogging in the future.
I am currently overseas, but I am going to do the filter mod to my right hand drive as soon as I get back!

If cleaning the T-junction does not solve the problem, then the IAC is obviously the next suspect.