I just noticed last night that there's a distinct rattling sound audible through the open sunroof, almost like marbles rattling in a can. So far, all I know is that this sound is coming from the driver side front of the engine compartment, almost as if from either the power steering pump or the AC compressor. I'll probably do more troubleshooting tonight, but thought I'd pick the wise minds on this board before I start. The only thing I have planned is just to check the PS fluid level. Any suggestions on what else?