'98 e300 turbodiesel 118k

I was just about to post a similar question when I saw your post.

My car starts quickly and without smoke. When in Neutral or Park it has either a regular rhythmic miss or sometimes an irregular miss which makes the whole car shake. This can happen, but infrequently, when the car is in Drive while waiting for a traffic light to change. It also seems to be triggered if the vent system is on and I press the EC button (economy mode fan: is on but not the AC compressor). I haven't checked to see if it correlates with the headlights. It also seems to get worse with deceleration.

Yesterday the "check engine light check electronics" message came on. Mechchanic checked the code and said it needed a mass air sensor. That was repalced but the problem persists.

PO had the new fuel lines (not sure if all of them) and O rings installed. I have tried to look for air bubbles but I am not sure where to look and haven't seen any even with the laser pointer.

I did the lubro moly diesel purge (thanks again crmont) x2 with no improvement.

Prefuel and fuel filter changed 4k miles ago.

Any suggestions?

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'98 E300 turbodiesel
117k