Help! Whistling noise at low RPMs

I have a 2000 C2. This morning when I started it up, I started hearing a faint whining / whistling noise at idle. When driving, the whistling lasts till about 3000 RPM and then disappears. The noise is quite prominently heard in the passenger cabin, but not on the outside. I opened the engine cover but still couldn't hear the noise too much. Sit inside and you can hear it clearly. Any thoughts? Alternator? Belts? It's probably not the fan because I would have heard it with the engine cover open. Saddest part: I didn't want to drive the car too much with that sound, so I had to miss the Bay Area drive to Carmel today. Any help is highly appreciated.

i have the same problem so any help would be welcome.

i get some whistling when i'm on the gas...i'm figuring it might be my air box filter, or throttle body. will probably just take filter out and put back in to make sure its seeded right and wipe the throttle body down with some starting fluid. i'll post if it works.

i was investigating it i think the air over the car blows over the snorkel type thing thats part of the air intake and its kind of like blowing over the top of a bottle.

well, i cleaned up the air box and the sound is gone now when i'm on the gas. my air filter seemed a little cockeyed (it was sitting a little higher on one side vs. the other).

I've heard of a whistling resulting from having the front hood adjusted too low. Some folks thought the hood was too high when they took delivery and adjusted it lower and found this resulted in a noticable whistle. As the air passed over the front bumper/hood seam.

OK here's my story, sorry it's long: Friday: I wash the car and clean it from the inside. While cleaning the inside I accidentally knock off the (aftermarket) Kenwood navigation speaker which is weakly attached by double sided tape to the dash panel on the right of the steering column (sort of where your right knee is). I think nothing of it. I just shove that tiny speaker in the back of the center console, from where it's wire originates. I tell my wife to remind me to fix it sometime. Saturday: I drive the car and suddenly hear the whistling / whining. Up and down with RPM. Only inside the car, nothing outside. I post on Rennlist, Renntech, call the previous owner (a friend of mine), call the warranty company, call the dealer, etc, etc. I am worried, I don't enjoy the soccer games, and I'm thinking of the car most of the time. I open the engine hood, rev up, rev down, go for short drives, read up on the alternator. Misery. Sunday: My wife asks me if it could be the tiny speaker. I say I doubt it, but lets give it a try. And voila, the noise was gone! I stuck the speaker (it had a mic too for voice recoginition) back in it's original place and it worked like a beauty. Thank God for my wife Drove the car all of Sunday and Monday and the whistle is really gone. I have a Ph.D. in Mechanical Engineering and my wife has only a Bachelors. I can't believe how stupid I am.

GREAT story! I'm glad it was a simple fix. "Book smarts" are great, but more often than not, good old common sense is what works best in the day-to-day world!