Engine Misfire at 2800 RPM

Hello,

My Audi 80 TDI is giving me trouble again.
The vehicle runs smoothly up to 2,800 RPM and actually pulls very well.
Above 2,800 RPM, the power is completely reduced, and then gently resumes at 3,000 RPM.

What could be the cause of this? Could the vacuum sensor on the turbocharger be stuck?

I am grateful for any advice you can offer.


Vehicle:

Audi 80 B4.
1Z 90hp TDI.
Year of manufacture: 12/93.
170,000 km

Does it produce a lot of smoke/exhaust in this area?

The 1Z has a wastegate, which means the chamber is operated under positive pressure rather than vacuum.
To say anything specific, you would need values for the boost pressure. Either have a boost pressure sensor installed or log those values using VCDS (VAG-COM) in that area.

Hello,

It produces a lot of black smoke at higher RPMs. Today, I also connected a boost pressure gauge. I noticed that the boost pressure builds up to about 1 bar from 2000 RPM. At 2600 RPM, it suddenly drops briefly to 0.6 bar and then quickly returns to full pressure.

When I disconnect the pressure hose from the wastegate, the boost pressure remains constant at approximately 1 bar above 2000 RPM.

Is it possible to verschandeln the wastegate somehow? Or will the pressure sensor stop working properly?

Thank you!