V6 TDI: Reduced Power at Low RPM

Hello,
Ich habe einen Passat 2,5 TDI Tiptronic AFB-Motor Bj. 1999 standart 150PS, Seit KM 69000 mit WKR-Chip (198PS/410NM). Now at 97,000 kilometers.
The vehicle always had excellent performance from around 1800 RPM and could reach a top speed of 235 km/h.
'Recently, the vehicle has been performing more like a naturally aspirated V6 gasoline engine, gradually building up its boost pressure. The full boost pressure of 2300 mbar is not reached until approximately 3000 RPM.'
The actual air mass value doesn't reach approximately 960 until around 3000 RPM.
At 2000 RPM, the boost pressure is only 1300 mbar, and the air mass is 600 kg/h in gas mode at 100% load.
The mass airflow sensor has already been replaced, and the turbocharger was replaced at 69,000 kilometers before it was tuned.
In the higher gears, the car still performs well and reaches its top speed of 235 km/h.
Recently, I've been doing a lot of long drives at high speeds. Could it be that the VTG (Variable Torque Geometry) adjustment is stuck in the high-speed position?

Does anyone have any idea what might be causing this?

saufratz wrote:

Recently, I've had many long drives with the throttle fully open. Could it be that the VTG adjustment is stuck in the high RPM position?

It might be... But before we start guessing, please check the duty cycle of the VTG control. If it's hitting its limit during acceleration, then the MSG is trying to achieve more pressure than the Turbo+intercooler system can provide (valve/turbo/control defective, or leak). If not, then something else is wrong.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.

Hello,
I just went to the VW dealership and have an appointment for Thursday to replace the turbocharger, which is still under warranty (only 7 months old). I'll post the results then.

Okay, here's the translation:

Thank you.
Best regards, Saufratz.

Hello everyone,
Just picked up my car from the mechanic. My suspicion was correct; the VTG (Variable Turbine Geometry) vanes were stuck in a position for high RPM. I now have a new turbocharger under warranty. Now it's running like new again.

Best regards, Saufratz.