Your Dist may be worn and the shaft wobbling. This happened to a member on Benzworld and I believe he had the Dist. rebuilt. I am pretty sure he is a member here also. In looking at the thread he posted I may be thinking of someone else but here is his write up.
http://www.benzworld.org/forums/r-c107-sl-slc-class/1374600-distributor-removal-repair.html#post2858839