Cold start whine
 

Time for another round of name that noise. Been happening a lot more frequently lately on my '03 S with around 93k miles. Wondering if anyone can identify what's making this high pitched whine that lasts around a minute or so on cold starts and then can also be heard dying down after about 5 minutes of regular city driving.

http://www.2shared.com/file/8265854/9958b43d/986S.html
http://www.2shared.com/file/8265909/9b5c56f2/986S-2.html

Water pump is relatively new, so I'm guessing maybe fuel pump?

You can hear it die down towards the end of each file. It's very audible, even from inside the cabin. Hard to pinpoint exactly where it's coming from with the engine cover on. This weekend I'm going to try and take a look with the cover off when I change the air filter. Any help is appreciated.

I didn't listen to your audio, but this may be related to the secondary air injection pump since it occurs under cold start conditions.

Amazing.

Today I went to leave work and after starting up I swore something sounded different with my exhaust tone. About a minute after starting I got a CEL and I used my durametric to read out Fault Code P0491 and P0492 which apparently indicate a faulty secondary air pump. I cleared the code and drove the 15 minutes home without it returning. Coincidentally I just had (and passed) my emissions test yesterday. Weird.