Originally Posted by Zacharias

Okay, for starters that is not serious rocking. Seriously. I have driven a DD for months that was waaaay worse. That is not unusual, but not 'normal'.

The motor sounds excellent so I don't suspect any injector or fuel delivery issues.

Setting up a smooth idle is a two-fold process, involving the rack damper bolt and the idle adjustment screw. As these cars age they each tend to have their own 'ideal' idle speed (at least in my experience).

The rack damper bolt compensates for end float of the camshaft inside the injection pump. It is only found on turbodiesels. There is an upgraded bolt, gold in colour, that many cars need to achieve a smooth idle.

Edit: see this thread: Idle problem