Clear all of your codes to baseline it. Then drive the car a bit.

Doesn't pulling codes tell you WHICH coil pack it would be? I recently had a coil pack on my wife's E320 wagon (1995) take a dump, and I pulled blink codes using the home-made blink code reader, and it told me exactly which pack it was (cylinders 2/5). Ordered a new one for $65 and 30 minutes later all good.

Starting over Christmas break, the car had some difficulty starting after not being run for 2-3 days, but generally ran fine once I got it started. Finally one day in mid-Feb my wife called me to tell me she was a mile away and the car was running extremely rough, almost dying at stop lights. She got it home and I immediately pulled codes, and found the culprit. A bad coil can have varying symptoms.