Auto polo 9n3 no power , takes very long to change gears , loud induction noise with stock airfilter

[JogiahMk4]

My cousins polo 9n3 1.4i automatic with the JC7 gearbox is now very sluggish, at around 3 to 4k rpm it refuses to accelerate, and doesn't want to change to the next gear. Changed the gearbox oil which smelled burned, not sure if it's related but the car is making alot of induction noise like it has a cone filter but it has a stock airfilter and there's no leaks in the airbox ,not sure if it's something to do with the throttle body