Dealt with a similar misfire condition shortly after putting in a new harness. Thought initially the electronic throttle actuator was the culprit. But it turned out to be much, much simpler. The suspects are the coil to plug connectors. Easy and cheap fix. Change all three of them. Search under the terms here, several posts on the topic. Good luck.

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In my driveway
1987 300TD Smoke Silver 300K
2000 E320 Wagon 4Matic 190K

Past MBs
1995 E320 Wagon 170K - Sold
1982 300D 200K - Sold
1986 300SDL - Junked
1987 300TD - Totalled @230K