Could this be a distributor issue?
I changed out the water pump on my 560sl not too long ago, a few days later I changed out a leaking EHA and "O" rings. Now I have a rough idle that is diagnosed as a bad fuel distributor.
During the water pump surgery I had to loosen the distributor to get to a bolt and in doing so I pulled it about 1" up and loose but not all the way out. I don't think I disengaged it but I suppose that I could have.
I am wondering somehow if I pulled it too far out and got it a tooth off, would that account for the lousy idle? AT TDC, the rotor points at the marks on the dist cap and the timing light shows 20degrees at idle.
I've run Techron through in the hopes that it was merely dirt somehow, so I may have to bite the bullet and get a new Fuel Dist. but I am not ready to concede it's need yet.