New pull away noise after cold start...
 

Happy New Year, everyone.

Ever since it turned cold about a week ago, when I pull away after a cold start, I hear a higher pitched whirring type of noise over the top of the normal engine sound under load. It's not super loud, but I hear it because its a higher frequency sound. Not squealy or screeching, just like a whir as I accelerate in 1st gear.

When I put the clutch in, the sound sometimes does a woo woo woo, and then I think it stops at idle.

This happens only when the car is stone cold, and by the time I've driven the car about a minute or 2 and things start to get warm, the sound stops completely.

My car is a 2006 997 C4.

Thoughts?

check water pump, mine did that for a month before it failed when I thought it was the belt.

The awesome Porsche shop here in Vegas, Trophy Performance, determined that it's the secondary air pump making the noise because of the cold weather.

Normal. All good.