Hey Konvict KROG, I've been researching and looking over a lot of the items that you have listed as causes for my surging idle. I may have finally found the culprit, or not?
The Dashpot. My truck does not have one? The little circular object with the bracket is there but there is no line or wire attached to it or the screw whichever is the actual term. Nor does it have the Throttle Stop Screw.
I'm not sure if its always been missing or not but this issue only happened after I had a toyota mechanic friend change the head gasket for me. And I can tell you now, I know he rushed on my motor because he left a couple oil pan screws off and the header wasn't tightened up all the way etc.
I can post a pic if needed.
I actually had no ide what it was the first time I took it off and because of the way it looked I assumed it was just a vacuum leak source.
If its what I am thinking its on the front of the intake with a short rubber hose hanging from a metal diaphragm deal that has a plastic housing dangling on it. In the service manuals it shows a oicture that says DP manual trans only. If you want to keep it sometimes the plastic dangling piece (filter) gets clogged up and changing it out with one that is new or clean fixes the problem.
Hope this helps