I found this issue over a month ago, I have been trying to figure out what the problem has been for a very long time but I really can't pinpoint it because there are so many symptoms that make it even hard to google the issue.
I appreciate any suggestions, really looking forward to getting to the bottom of this.
Here is a list of symptoms that I have:

1. Idle sticks at 1.5k for a second when letting go of the pedal (IF I very very lightly press the pedal, no matter what it will go up to 1.5k)
2. When driving and letting go of gas it seems like the car pulls me back and instantly loses power (maybe tranny?)
3. Idle rpm likes to jump a lot, usually it'll idle at ~800, but it may shoot up to ~1.2
4. idle jumps more when AC is on.
5. ONLY on hotter days (more than 1 degree Celsius) my car will stall when idling, here is a video that shows exactly what happens in the TSX
6. After the stall I will get a check engine code that reads P2102, but it goes away after a couple hours.

I've tried cleaning the throttle body, no success. I have yet to check for vacuum leaks, I will do that today. I also noticed my engine air filter box is a little loose, because the back bolts are stripped and don't tighten it down.
My car also shakes at idle a lot, but smoothens out when it warms up. However I have aftermarket engine mounts so nothing surprising. Could the air lines going to the engine mounts be cause a vacuum leak if they are disconnected?

 

yes, if the motor mount lines are disconnected and NOT capped off at the intake manifold, it could cause a vacuum leak.

I think you should look for hoses that are cracked, broken or disconnected...then plug it with your finger or clamp it somehow to see if that line is the culprit

 

P2102 is actually the throttle body actuator control module...

I would also start there

 

Is that the actual throttle body? Or is there a module that goes on these?
If so where can I find them?

 

Since I have no clue as I dont have the same car as you, the best we can do is Google to find more info...
when I googled "P2102" that's what the code came up as...."throttle body actuator control module..."

so,now, we can input "throttle body actuator control module + TSX" into gooogle

which yielded this page:
https://www.google.com/search?q=thro...hrome&ie=UTF-8

from this page; the first result is a PDF; throttle actuator control module replacement - TSXClub
click it and its a PDF on how to test each component to see if it's bad

 

thanks boss, believe it or not I've been googling these issues for a while. Never had that thread show up for me, I'll look into that PDF today.

 

now you know what the code means... keep googling the code + tsx + weird idle to see if you get more hits...


all the electronics under the hood uses voltages...when testing, they should give a certain voltage....if not the correct voltage, that's your bad part.
you will need a multimeter.