2005 2.7L Manual 4x4 High pitch noise followed by vacuum noise when starting

When I start my 2005 tacoma with 2.7L 4 cyl I hear a high pitch whine/hissing noise for about 10-20 seconds followed by a vacuum let off noise almost like a turbo blowoff valve then the whine/hiss goes away. This only happens during cold starts or when I haven't started the truck for a little while 30+ minutes maybe. I have read that this may be ABS or emissions equipment, but I am skeptical because it doesn't seem like many people mention this noise. Is this normal?

 

Fan Clutch maybe?

Open the hood and start it cold and listen to the fan clutch...

 

Pop the hood and look in front of the airbox on the passenger side right up at the front. It looks kind of like a muchroom and has a hose that runs to the cylinder head. That is the source of the sound. It pumps air into the exhaust when the engine is cold in order to burn off the excess fuel from the rich startup mixture. Its normal, leave it be.

 

Thanks shemp this does seem to be where the sound is coming from!