'08 535i

[JHG535]

This engine is newly rebuilt. It ran flawlessly initially.
Everything on it is new, including the throttle body, coils, injectors which are 13's.
The car runs perfect until I get a TB oscillation (12-1400 rpm)which makes the car undrivable.
Until recently, a reset lasted for days. Now it's too frequent to drive and I had to tow a couple of days ago. It does seem to have a slight surge while driving which is barely noticeable to my passenger, but it is there.
No vacuum leaks, I replaced the TB wiring harness and tried two "known good" TB already.
My codes are:

1. 2cfm-Throttle valve potentiometer2, plausibility to air mass

2. 2cfb-Throttle valve adaptation value

3. 2do9-DME throttle

Any ideas or suggestion?