I have the same problem on my '85 and it doesn't matter what brand parts I use.  The distributor is new so I doubt that is the problem.  There was a string about dirt from static build up and the fix being a conductive plastic cap, but I didn't see the whole thing, so I'm not sure if this was the problem.  If it was the problem, I'd like to know how to get one, you too I guess.
Craig Rogers
Ineffable Audio Unity Inc.  
The song of Life envelops the timeless void.  
                   Its name is...IAU
      Specializing in Uher tape recorders
      (914) 378-1606,  carogers@idt.net