Bocken and Rauch + Nailing, no performance

Hello,

I hope you can shed some light on this:

I have a Volkswagen Passat 3B, 1.9 TDI, 130 horsepower, manufactured in 2001, with 150,000 kilometers on the odometer.
AGR is disconnected and blocked, turbo is OK, exhaust is OK, catalytic converter is OK, mass airflow sensor is OK (although it was replaced!). The error memory is empty.

At 2000 RPM, the car jerks violently (a really hard shudder!) and becomes extremely loud. It makes a very loud knocking and clattering noise! The speed doesn't matter at this point. It barely accelerates, and at the same time, it emits thick black clouds of smoke from the exhaust. At 2500 RPM, the power completely cuts out, even with the accelerator pedal fully pressed. And the noise... it's something else.

Does anyone have any idea what else we need to look at to get to the bottom of this problem (which has been slowly developing over the past few months and has been getting worse)? Any help is welcome!

Possibly, the wiring harness to the power distribution units is faulty. Please use the search function.
Can you create a log?