So several months ago I posted a thread related diagnosing an engine ping. The long and short of it was that my car made, what sounded exactly like a pinging sound when I was accelerating from 2500-3000 rpms. Well my fellow :SNSign: members were able to help me rule out that it wasnt a ping, but I was never able to figure out what it was. Today however I figured out what it was, the backing plate/shroud for my front left rotor was loose and rattling, but for what ever reasons I could only hear it at the above mentioned rpms... It was just barely loose, but it was enough to cause the sound. Anyways if anyone has a mysterious, marbles rolling around in a coffee can sound it wouldnt hurt to check out the backing plates...