My 03's turbo started making a buzzing sound the other day. I was going up a grade and had to stomp on it to pass a truck when it first started. It has gotten better but is still there on accel and decel. It sounds like a fan with bad bearings. It whistles like normal then just when the whistle is about to
stop it makes a buzzing sound like the blades are vibrating on the shaft. I took it to the dealer and they said($100 diagnosis) it is my aftermarket exhaust. It has never made this noise before and I don't believe it is the exhaust.
What do you think?