Why does it looses power when accelerating at any speed?

Hello, without hands on / first hand experience from a technical perspective on what is happening, it's wide open to guesses. You could have an engine misfire, causing rough running and noise. You could have some kind of timing issue, causing spark knock and vibration and lack of power. You could have a lean running condition. One thing for certain: a skilled, qualified and experienced technician will be able to fairly quickly determine which direction to go to diagnose and repair your vehicle. Seek that guidance for help. Note that if you try to continue driving, you can cause more harm to your vehicle and some very expensive components. Good luck. https://repairpal.com/repair-shops/volkswagen-repair-and-service-in-avondale-arizona