high pitched engine whine?

[kellikans]

Hey all. I noticed this morning that there is a high pitched noise that sounds like its coming from the engine upon acceleration. it stops once I hit 20mph or so. no noise upon idle, but you can very slightly hear it when revving the engine. it was pretty cold this morning (in the upper 30's) and this is the first time that I've heard it. any ideas? could it be as simple as a loose hose? I'm taking it in on Monday for a couple of other issues, but wanted to see if anyone has experienced the same thing.

btw, 2009 4.8i, 34k miles. thanks!