I've got a puzzling noise that seems to be coming from the engine compartment on the drivers side possibly near the firewall. I just started noticing this sound about a month ago and it's been intermittent, so it hasn't been a big issue, just annoying. At first, I thought that the noise was A/C related, as I've been using the A/C pretty frequently since its summer and its been hot. Lately, the noise has become more frequent and happens when the A/C is not in use as well as when it is in use. The sound resembles ruffling a bag of leaves around or a metallic kind of ruffling around. It gets louder or more pronounced when the RPM's rise. That's the best I can describe it. It happens while driving straight, under load, not braking or turning. I notice it more when the RPM's are higher and the car is under more load and/or more than light throttle. 1/2 throttle or more. One of my Tech's at work first thought that it may be a bearing in a pulley or something, since the pulleys are on that side of the vehicle. After putting the vehicle on the lift at work today, now we're inconclusive on our thoughts. We were able to duplicate the noise with the vehicle under load while off the ground on the lift, but not able to diagnose where or what it's coming from. The tech thought today that it could even be an exhaust leak or something. Unfortunately, it's tough to describe the sound and it doesn't happen all the time when driving.

**Any thoughts, ideas or similarly confusing noises?