I'm in the process of diagnosing a rough idle on my 300D Turbo.

From 700 - 1400 the car has a shimmy/shake that increases as rpm's go up from idle untill about 1200, then decreases until about 1400 where the engine is smooth. So far have done:

Valves (almost all were tight)
Diesel purge
Cleaned & Balanced injectors (pressure was 140,125,130,130,130)
Replaced both motor front mounts
Replaced 1 engine shock
Timed IP at 24 BTDC
Cracked injectors lines at injectors - similar change at all 5 cyl
Tank screen and both fuel filters changed
Checked chain stretch (simple method via cam and crank marks) +2 deg ATDC
Compression 375 or better
Vacuum leak at fuel security latch - fixed the door lock issue
ALDA - hacked and already fully turned CCW - going CW 1/2 turn made performance worse


When i bought the car (my first MB) the idle was set high, which i did not notice but which was pointer out to me by Abe at MBMW Parts here in Seattle. When we tried dropping the idle from 900+ down to 700+ the engine shaking would start which led to the list of fixes and maintenance issue addressed above. But i still have the shakes and what bothers me more, poor mileage (under 20).

Attempted the 2mm timing chain stretch test but could not get the dial gauge to be still, so i lined up to cam and crank marks as listed above - not the greasiest but a good indicator of general health. While there i started looking at the cam too which i found to be pitted on at least 2 lobes - could this be the problem, a poorly ground cam? Engine has 215k, with a rebuild about 70k ago.

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1985 300D, 250k
1980 300SD, 180K