I finally found the time to change out the plugs today. Pulled the Bosch platinums and replaced with Bosch copper core. New plugs are in, gapped and properly torqued (I might add, the first time I have ever torqued a spark plug). The idle has smoothed out considerably.
The platinums looked good after one years use, still close on the gap and fairly clean, with only a small black spot right at the platinum electrode. Tomorrow I will give it a short highway hop and see how she runs, during and after.
I checked out the plug wires while I was at it. They look OK, but will need to be changed by the end of the summer just because I don't know when they were last changed by prior owner(s).
I am thinking the rough idle had been there for some time, one of those thing you kinda don't notice when they first start out. Like the changing wheel alignment, as it changes you subconciously correct, never realizing the alignment changed. The roughness was probably there before the Benz went down for the steering pump repair, but I didn't notice it until starting it up after three weeks of down time.
73 280 SEL
[This message has been edited by MikeTangas (edited 06-11-2000).]