"No vacuum leaks that I can see"

The first thing I check on an older VW motor are the vacuum lines, at the connection points.
The braided material can hide cracks in the rubber underneath, so inspect each line carefully, by pulling them off.  Sometimes just cutting them back 1/2 inch is all you need to do to get a tighter connection or get past the cracks or swelling in the line.  
A relatively quick and easy thing to check on your annual inspections.  

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Chris S
Sent: Monday, April 20, 2020 2:53 PM
To: vanagon@GERRY.VANAGON.COM
Subject: No idle when engine cold

Engine: 2.0 ABA block, 1.8 head, Digifant II.

I recently replaced the head gasket.  The head was skimmmed flat.  ARP studs.  All looking good.

- Timing good
- Temp II sensor tested good
- Throttle switches work fine - tested.
- Idle control valve buzzes
- O2 heated sensor produces voltage.  Swapped with my spare and no difference.
- Re-checked grounds that I could see.
- No vacuum leaks that I can see. 
- New plugs
- New wires
- New rotor and button

Symptoms:

-  Engine will not idle until it warms up a little.
-  Engine runs well above idle
-  When unplug Temp II sensor rpm drops, engine sputters and dies.
- Sometimes if rpm drops, engine will sputter/stumble, sound like it’s very “cammy”, then clear up.

I’m stumped.  

All connections are connected.  I cleaned the throttle body with carb cleaner.  Could I have clogged something?  Some o-ring did not like the carb cleaner?  Do I have an exhaust leak north of O2 sensor that I can’t hear?  I did loosen and re-torque the header for better sealing.