is it more of a girgling sound, then when you give it a little more gas, it goes away and the tone gets deeper?
If it is, I get that on my 07 QC Hemi right after I put the K&N CAI in. I think its because I removed the big Hemi hat "Baffle" so the sound is more noticeable.
I also heard that it may be the EGR valve but not too sure about that...
Stock for now!