Hi guys! I own a 01' B5 A4 Quattro 2.8 just hit 90k and today I started to notice that intermittently I hear this air rushing noise upon acceleration say from a red light or stop sign and then it kinda goes away once I get into higher gears... and then other times the car sounds and accelerates completely normal without the jet plane sound...

so the car is reading no codes at all and everything seems to be in working order & All gauges temp and oil, etc reading proper.. My first thought was maybe bad Clutch Fan??? It's more or less an off and on problem but it's enough to be totally annoying and the car almost feels a tad bit sluggish when it does this jet plane noise.. any ideas? Thanks!

 

I'd about have to hear it in person to tell what it was. Since you're not getting any error codes on the ECU makes it even stranger. But.. Check the air intake ductwork from the outside air pickup to the throttlebody making sure everything is tight with no leaks. Also open up the air filter box and look for anything strange.