cardboard-in-fan noise at 2-2.5k RPM
 

I'm hearing a sound that sounds like a piece of cardboard being hit in a slowly rotating cooling fan between 2000 and 2500 RPM. This happens at any speed and occurs exactly at 2 - 2.5k RPM. Dropping to 1.9k RPM eliminates the sound, moving to 2k from that, and the sound is back!

This only occurs during throttle application. Also, you can't hear it outside the car.

Does anyone else hear this? Is it normal?

If you have a manual transmission, then yes, I hear that noise too.
I made a >>> thread <<< about it too.
I'm pretty sure it's normal.

I have an automatic.

Oops, sorry, I missed that.

OP I have Auto and I have the sound too! You are not alone!

I have this sound as well. No worry though.

I'm starting to think that it's a couple of plastic pieces that might be hitting each other at some sort of harmonic frequency. Also, the sound doesn't seem to be heard outside the car, which suggests that at least one of the parts is physically connected to the firewall.

I noticed this seems to only happen in 4-6th gear.

Could it be a sound coming from the noise generator?