Unsteady Vanagon Idle When Warmed Up

[fewil]

Unsteady idle after warm up: My 2.1L '89 Vanagon idles at a steady 8000 when cold, but after fully warmed up the idle oscillates from 1000 to 1100. This happens very consistently. I have a new Idle Control Unit and Electronics Control Unit. I swapped these for the old units with same results. I have new Fuel Injectors, Idle Stabilizer Valve, and Fuel Pressure Regulator. My Air Flow Meter is fairly new. The throttle switch clicks. I can't find any vacuum leaks. Can you offer any suggestions?
Thank you.

[ALIKA T3]

Could be a leak in your intake runners/plenum/TB, or advance is wrong.
_________________
Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[jlrftype7]

When you say you can't find any vacuum leaks, have you smoke tested the engine , or just sprayed Brake Cleaner or Carb Spray around while it's running?
Just trying to clarify.
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto