BMP 2.0 Shakes After Oil Pump Failure

Hello.

I have what you might call a bucket without a bottom here. Since it's my son's Passat, I'm trying to salvage what I can.

Regarding the history:
The oil pump module failed, so my dear drove on with a trailer and a second car, uphill for about 4 km to the next exit. Without oil pressure.

Then we repaired the module, and the oil pressure is now present.
We replaced the turbocharger and are trying our luck again.
After approximately 500 km, the engine is losing power, and it's idling roughly.
Replaced the tandem pump, as it was no longer producing pressure.
Although the pressure is now correct, there's still no power and it's still sputtering.
PD elements were removed and sealing rings were replaced, but without success.
Boost pressure, compression (26 bar when cold), camshaft, tappets, and particulate filter have been checked and are in good condition.

The stopper in the rocker arm shaft was also missing, but it has been replaced.
Okay, so it starts well, and it runs smoothly when cold, but when it gets warm, it starts to idle roughly, and the overall performance is around 40 percent.
Here's another strange thing: The MWB 13 completely freezes when idling, and the fuel consumption display on the instrument cluster shows a ridiculously low value, for example, 2 liters per 100km in a 30km/h zone.

No error codes found.
I'm currently at my wit's end, maybe you can help me.

Best regards, Trogi.

Hello,

Autoscan?

Sure, here is the translation of the text from German to English:

"LG" is an abbreviation for "Liebe Grüße," which means "Best regards" or "Best wishes" in English.

I will do that. Tomorrow.

Harness for PD (Power Distribution) components...