My 601 (84 190D) did this. Real rough at idle but ran great at higher rpm's. I tried everything. It turned out to be a bad tensioner and a stretched timing chain that threw it out of whack. In retrospect it makes sense, but I had several shops look at it with different suggestions (including one that said the engine was tired).

Incidently, from that point on I have done all my own work on the vehicle. The problems were at 212,000, it now has 306,000 -- and it still is not tired.

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Jovan

'84 (11/83) 190D 2.2 5-Speed; Silver/Blue; Motor No. 00354, 402k mi (340+kmi mine)

'89 Porsche 911 Turbo Coupe; Black/Black; 53kmi
'05 BMW 530i 6-Speed; 302kmi
'19 Range Rover; 30kmi