Along the way one of my keys stopped working. It would operate everything at ignition position I and II, but it brought a "Start Prevented" error when trying to start the engine. That left me with one operating key, and with thoughts of the cost of being towed to the dealer and having 2 ne...

No, never figured it out. Decided not to worry about it. Car seems to be running fairly well. Thanks.

It didn't seem to have a cyclical nature to it, it seemed more random. I am going to take it out again tomorrow and try to learn more. I'm not familiar with brake shield. But I would think if it was a rock that then was ejected, the noise would stop. And that scenario wouldn't, I think, approach the...