2 years into my S60R swapped XC70, and I am SO close, but am stumped again...

[Tumbler510]

Got the car running with MT software thanks to Mat Leavesley (legend). The car ran fine before the swap, and I've obviously taken my sweet time getting it going. (This has led to a few smaller issues where I unplugged/unscrewed something and forgot about it later) The car has been turning over fine, but idle was steady around 900 then would jump to 1.5k, then settle back to 900, then jump back.

I removed the TB and cleaned it, as well as the MAF. Now this is what the car runs like:
1. 0 throttle to begin with, and it seemed like it was going to stall.
2. Gave it some throttle and it acted fine.
3. Got the RPMs to 2k, and it did whatever it shows. I as not giving it throttle when that happened, and I had to turn the car off because it wasn't settling.

https://www.youtube.com/shorts/IjZksZ-s9gY

Codes after that run:
CEM-9C03: Antenna/light ring Signal missing
CEM-8F52: Relay, Headlamp Wash/Wipe. Signal Too Low Or Signal Missing
CEM-1A62: Communication With The Engine Control Module (ECM). Signal Missing
CEM-1A5F: Communication With The Brake Control Module (BCM). Signal Missing
CEM-8F25: Relay, Windshield Wiper. Signal Too Low
SRS-DD10: Communication Control Module. Faulty Communication

NOTE: The Brake Booster Vac Switch runs 100% of the time the ignition has power. I unplugged it for now, and the pedal is pretty soft, but still stops the car (I did the S60R brake swap and bled them last week).

Any advice on where to start troubleshooting? I am thinking wiring.

[BlackBart]

Does this system have an idle control valve?
Our old BMW E30 had a faulty original ICV and it would cycle up and down like that.

[vtl]

Read the fuel trims (STFT, LTFT)