Known camshaft issue on an AGU?? keen to hear about that one. Fuel cut ?? under WOT, You have a Gti Mk4, im sure itll be boost cut, Check your vac line to your wastegate. Common to turn to sticky goo and stick together and stop the wastegate opening properly, this will over boost and cut the thing big time, seen it lots on the Mk4, been with VW before the internet came about ( sorry had to drop my new line for the google mechanics and in no way aimed at you my friend, just wanted to christen it) but havent seen any cam issus.
Technician before the internet came about
Audi/VW/Porsche Factory trained tech 24+ yrs exp