Limp mode/overboost

Hi everyone new to tdi forums.
I have a 2003 mk4 gt-tdi (ARL). I bought the car 3 months ago mapped to 190bhp and arround 450nm torque, this was told to me by the previous 8 year owner of the car. The car ran great i did timing belt and waterpump at 160kmiles and also a full service. Recently ecountered limp mode but get this only at 120mph.. Alongside this i feel a loss of power and allso seems the turbo is boosting late. For example in 5th gear bost doesnt really come on until 2.5k rpm. I get the fault code charge preasure controle positive deveation. I find it weird tho this only happens at arround 120mph. Any ideas anyone? Please forgive me if i left out important info or posted this in the wrong page.

Could be a lot of things.

The actuator on the turbo is not adjusted correctly, turbo vanes sticking or more.

Do you have VCDS to log the boost & MAF values?

Limp mode at 120 mph ? Gotta get that fixed.... can't be dilly dallying around all day !

I never had this problem when i got the car 120mph was a walk in the park no with no stress. Now 120mph feels like a top speed. I got under the car today to check the vacume actuator and it moves freely when i turn the engine on/off. Im going to get the revive turbo cleaner anyway to clean the turbo ive read good reviews about the product. Also today i notice the aftermarket intake pipe was loose near the egr or just above the egr , i did a a quick fix to see if this improves boost. Really hope i get to the bottom of this soon as the lack of power is really anoying.