All of my 3.3's and 3.8's have made this noise. Most of you probably know what I'm talking about. The pulley's make it. Idler pulley and tensioner are the culprits I believe. I know I can replace them with new ones to shut the noise up but instead I pulled out my trusty can of PB Blaster.(and honestly I'm used to the noise) I covered the belts up with some shop towels to keep the slick off the belt and doused the center of the idler pulley and tensioner, around the bolt and into the crevice around it and let it soak for awhile then cranked it up. I didn't think it was going to do anything because most of whats in PB Blaster does as any "lube" and rust inhibitor does and evaporates but lo and behold when I started it...complete silence at the pulleys(aside from the whining power steering pump). This stuff really does creep into crevices as it says. It's been a couple of hours and it's still quiet. It has been SOOO long since I have heard them this quiet, it's very nice actually, though I'm not sure how long the silence will last. This stuff has also saved me many headaches at getting broken exhaust flange bolts out of an exhaust manifold.