When I turn my car on and its been on for a few seconds theres this loud whistle (you can hear it for a few seconds) and the car goes back to normal. Car seems to run fine. I just dont know if theres a deeper problem. Any ideas?

 

Through the speakers? If so it could be a ground loop issue????

 

Ive been told thats the turbo on a warm up cycle from the previous owner, i only hear it occassionaly anybody confirm this.?? I actually like it sounds pretty tight.

 

MY TT does the same thing, it sounds like some type of air pump under the hood, and it only happens occasionally, most likely when it's cold out. I was told it was an emissions pump, but i haven't had an troubles come from it yet and i have had my car for 20k miles and 1 year.
Justin

 

the sound could be the secondary air injection system

 

It does only happen when the car is cold or hasen't been run for a while. But the damn thing sounds like a banshee. It seems like its coming from the intake side. By the time i get out of my car and get up to the front it stops. The car does seem to be running fine. Is it something to worry about? What caused this to start?