A4 2.0T FSI engine knackered!
I would check your turbo boost levels, to avoid engine damage.
Have you a boost gauge fitted?
Either way, I would get the car checked on a local dyno with VCDS check too.
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Audi A4 B7 2004 red 2.0 TFSI Quattro Sport saloon, Servotronic steering, MFSW, CDIS, DRL with Coming Home, auto dual xenon lights/wipers/mirrors, split folding rear seats, 3rd headrest, centre armrest, Isofix mounts, RS4 rear ARB, pedals & carbon dash trims; Audi TTS 9Jx18alloys (2 sets), Yokohama AD08 summer, Conti TS830P winter 245/40/18 tyres, TPI 15/20 spacers/lockers, Pipercross filter, GFB DV+ turbo valve, NGK BKR7EIX plugs, Osram Silverstar Xenarc D1S bulbs. Build thread