03 CLK 320 - Headlights dim at stoplight
 

My '03 CLK 320 has had this annoying problem for quite a while. When at a stoplight at night, I notice that the headlights dim for a split second, and then recover. The engine also feels like it's about to stall, but recovers as the lights come back to full brightness. I don't notice it all the time, but it is probably happening more than I know.

The other night, it happened and the engine shut down completely. It wasn't a total electrical shutdown, though - the dash was still lit and a "malfunction" error flashed briefly with what looked like a battery icon. There wasn't any more info on the screen except to say "see service station" and the message didn't stay on very long.

I was able to put the shift lever in park and start the car again immediately, and I was able to make it to my final destination.

The car has about 190,000 miles and has been very reliable. The battery is only +/- a year old, and I did replace the cam position sensor several years ago. I checked the the alternator with a volt meter and it is producing electricity.

It starts fine now, but I am afraid that it may die on the road again. No malfunction error shows on the dash now.

Does anyone have an idea as to what is causing this?

Thanks!