Here's an update - unfortunately I still have not found the issue
I re-seated the TPS and make sure its not causing tension on the throttle plate. I re-sprayed propane around everywhere I can think of. But nothing...
Now I also have a 2nd strange problem - whenever the car is heat soaked, it will idle waaaayyyyyy lean. I'm talking about going from "normal" AFR of ~14.9 idle to 16.5-17.0! And this condition also causes lean surge until I get to ~2200rpm (slowly).
That kinda makes me think that there's definitely a small leak that magnifies itself as hot air is less dense?