'84 PCM 351 not firing on #4 cyclinder @ dizzy

[EDGE]

Its a strange problem, at least to me. The #4 cylinder gets no spark. I've replaced the plug, all wires and the dis. cap and rotor. All other cylinders fire fine. The problem is at the distributor. There is not spark when I look for it at the cap. All others have spark.

Its a points style with pertronix electronic conversion. This just started happening this weekend.

At first it was intermittent, I could notice the engine bogging and then it would come back. The next day the bogging was more frequent and now it is constant.

Anyone know what I should check or be looking for in this dizzy?

[EDGE]

I think i figured it out. There are 8 little magnetic key on the ring that goes around the rotor. It looks like a spacer. One of the little magnetic keys was missing. Calling Pertronix on Monday for a replacement. I just go with the Mallory dizzy. Its $280 at Summit Racing.

[DAFF]

I bet if your turn the engine over the missing key corelates to #4 spark on the distribitor.