[McMetz]

hello to all i'm new to the board

i have a question and it is, i hear a whining noise somtimes it doesn't do it all the time, sometimes after i have been driving for awhile or when i start up, i only seems to do it when the car is stopped and i'm fixing to turn it off or right after i start it. It also only seems to do it when the a/c is on. i read somewhere that it might be emission control. any help is greatly appreciated.

i have a 2001 boxster

thanks