While driving to work on the highway, I noticed an odd sound coming from the right side of the car. I pulled off and looked at the from passenger wheelwell.

It looks like what happened is that when I was parking, the curb slide under the front of the car and broke the rubber or plastic rock guard loose from the front side of the wheel well. The guard curves back so it was rubbing against the tire at high speeds. A big chunk had already been worn away (as if a small shark had bitten the middle third of it off. I popped it back into place and drove to work.

That night as I was driving home, I heard the same noise, then a BIG clunk as the entire thing ripped off of my car and went tumbling behind me on the freeway. When I looked at it more carefully, there's now a small sensor dangling from where the piece came off (possibly the temperature sensor a visitor to this site mentioned). Coincidentally, my "Service engine soon" light also came on. This is the "take care of when convenient" light that comes on when the emission system isn't performing at 100%. Since it wasn't flashing, I'm going to sit on that repair for awhile.