More info collected.

I noticed oil from the contour hoses, both, the one going to the breather and the one going to the air distributor, as if it had a bad PCV valve.

I changed the oil 30 days ago and have about 750 miles on it since. The oil is very clean.

The engine will sometimes run very smooth and on the scope the waveform will clear up during that time, very short about 10 sec., then back to rough.

I can adjust the fuel/air to 22” at idle, but it is very rich. I have it now at 16” at idle and under load (drive with parking brake) it will drop to 15” and hold steady (no bounce).

I pulled all the plugs and the good seven cylinders looked great, light brown. The bad #2 cylinder looked mildly oil soaked. This may be fuel soaked?

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1983 500SL Euro