TDI Golf III: Performance Loss Troubleshooting

Regardless of the engine speed, my Golf noticeably loses power after accelerating to approximately 120 km/h. Further acceleration is only possible on a flat surface or downhill. The effect seems to be related to the speed: everything is fine below 120 km/h, even at high engine speeds. If I accelerate aggressively, the problem occurs as early as around 100 km/h, but if I drive more cautiously, I can reach approximately 140 km/h.
So far, I have already done/checked:
All sensors and injectors have been tested with a multimeter. All are working correctly and receiving voltage. The fuel filter has been drained: it was empty of water.
Exhaust gas recirculation (EGR) valve: After manually actuating it several times, it became easier to move, and I was also able to move it (slightly) by pulling on the vacuum hose.
A friend read the error codes.
00575 - Intake Manifold Pressure
17-10 - Control Difference - Intermittent
Once, a weasel chewed on an air hose (for the turbo?), causing similar symptoms, which I investigated but didn't find anything at the time. Could it be that again? Who knows the answer? But: I'm not a complete expert yet, I'm still learning how to work on TDIs. However, I'm not completely clueless. And I'm not a fan of dealerships.

Thank you and best regards.
Peter.

1. Search is your friend!

You can find plenty of information about the 575.

2. If you find an error, then usually do the following:

- Note down errors.
- clear errors
- Test drive (once, if possible, without the problem occurring; once, deliberately provoking the problem).
-> The error should only reappear on the second attempt.

Then you have already proven the connection to the code problem .

Then you can investigate the code and its possible causes further (by searching here in the forum).

m;

P.S., very important: Is it a 90 HP or 110 HP engine? This completely changes how the turbocharger boost (manifold pressure) is controlled (again, search for technical articles about vacuum in VP37 engines).

Hello Dieselmartin,

Thank you for your reply. It's a 110 horsepower engine. Thanks for the search tip, I'll do some more research. I'll take care of the test drive myself.

Cheers!
Peter.