Inconsistent idling problem

Precisely why I posted.
I asked around the site for months and nobody ever offered up the throttle shaft as a possible leak... or really offered any detailed explanation of what would cause the idle to change. I'd say using smoke to pinpoint a leak IS solid diagnostics...and experience comes from trial and a lot of being wrong. ;-)

Hopefully the OP has an easier time finding the problem.

Well I don't know where I was when you were going through that, but you also know how often a suggestion falls on deaf ears, or gets lost in a sea of suggestions.
I agree on the smoke machine and I am sure it would have been used if we had one, but it just never came up.

And as far as "being wrong" my wife must think I have a ton of experience in that case. :D
I could tell her that the sky is blue and she would go to Google for a second opinion.

That reminds me of this.