New to forum, need help

[Evil Ed]

Hello everyone I just picked a clean '06 Imola Red 4.4 . Love it, fun to drive. Just recently I noticed a for the lack of a better term a "whine" only when I'm idling. Not a supercharger whine but different kind of wine. The odd thing is sometimes it is there, other times it is not. It is really annoying and I am embarrased when I am at a light or having stopping at the gate guard for id check at AFB. I know there could be any number of possible solutions but thought I might throw it out there and see if this might be a common issue on these vehicles. Also I am not throwing any service lights either. Thanks for the help everyone.