I am having trouble figuring this out and need help, it is a 2002 TT Q 225, idles smooth, and drives great if you are easy on it. However if you accelerate hard from a stop, passing, brisk on ramp etc. I get a loud screech that sounds exactly like a belt squeeling and abrupt power loss, backing off the gas brings everything back to normal.

This happens as the motor revs past 3000 and and starts pulling hard, it does not sound like air at all and I have found no air or vacume leaks. I can rev to any rpm in neutural and get nothing abnormal or any kind of unusual sound.

the car is well cared for, 98000 miles with no modifications or aftermarket parts.

Thank you for any help.