Still sounds like too much air. Afmcorp, verify that the AAV is closing!
If so, (George, sounds like you are sure that yours is okay) close the idle air screw until cold idle is no higher than 1500
, and see what value it settles down to when warmed-up (~500 is okay).
Vacuum leak is a likely culprit if you can't get the idle speed down enough even with the idle air screw fully shut (and the AAV is closed, of course). I would venture that smooth running in gear implies reasonable injector/manifold seals (leaks here affect one cylinder at a time causing rough idle). Definitely check the breather Y-hose between the idle control and the intake manifold.
Peter, just curious, re valve clearances in your 4.5, I'm surprised how much tight exhaust valves affect idle smoothness. Do you know why?