Intake Manifold Pressure Problem Solved!:)

Rust was the problem!

The rod connecting the vacuum sensor for the turbocharger pressure regulation was heavily rusted! With a lot of rust remover, a long lever, and a whole lot of force, my friend managed to get the rod working again.

I guess it's because I don't drive much on the highway, only constantly in the city, and apparently the strut doesn't come into use there. Whatever. Now there are no more speed limiters, and you can reach your 160 km/h quickly again on the highway.

Thank you very much for the help here in the forum.