Just wanted to follow up with a thank you to all who chipped in their expertise, and make sure the solution got into the archives for anyone else in my situation.

Broke a rear shock about a month ago, so I just parked the car until I had a chance to work on it over the holidays. (Never seen a Bilstein shock come apart like this one did, but I digress...)

I borrowed an oscilloscope from work, and spent a little quality time trying to get a look at the inputs and outputs to the three coils. One appeared to have a slightly lower output than the other two. Not enough I would have necessarily expected the misfires, but enough to notice. Sooo, I very scientifically decided to throw parts at the problem. Installed three new coils to go with the new plug wires and connectors. Figured if one was bad, I'd just as soon get them all.

Problem is GONE! Yes, coils do go bad. Good to have things back the way they were meant to be. Much more fun to drive a properly running W124 than the beater W123 diesel.

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Gary Thompson
Georgetown, TX
1995 E320
1984 300D