Well, I did the "4 Ps" under the car for the better part on an hour and didn't find anything (except that the front seal on my diff is leaking ). So I started expanding my search a bit and that's when I made a startling discovery. My battery had worked its way loose from its mount and was rattling around in the left rear fender well! So I shoved it back into the mount and tightened the bolt. All is good now! Thanks again to all who offered suggestions

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"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles