328 - Ignition Loss on One Bank

A couple of things about the distributor caps. You should probably get new cork gaskets, the old ones can crumble with heat/age. As the caps are expensive, they are not typically changed as frequently as on a more conventional car. The plug wires do not just press fit in like most caps, rather they have little piercing screws inside the cap that pierce through the wires and hold them in place. So you don't just pull the wires out, you take the cap off remove the piercing screws and then the wires come out. To put back on, you cut the old pierced portion of the wire off, insert and and pierce on a fresh new section of the wire.

There is a little carbon button on a spring inside the cap, which contacts the rotor. This button can wear out, and there is a spearate part number to replace this. If the cap itself is ok, ie. not cracked you can clean the contacts with a dremel tool brass wire brush attachment, replace the carbon button if worn and reuse the cap. The rotor is nothing special, straightforward to bolt on and off.

Normal tune ups for cars of this age would include new plugs, caps, rotors and wires (and plug extenders which tend to fail more than the wires themselves). But the cost is high for all these parts, so they are often not replaced, and as noted the cap can be serviced rather than replaced. Given your description of what was done (and not done) to the car 4,000 miles ago, I am guessing your problem is the carbon button is worn down inside the offending cap, or the rotor is worn, as you do not indicate those were addressed in the service. It is possible the cap contacts were worn, so even though they can clean up the gap between those contacts and the rotor with its normal wear might have widened to cause the problem. Although this would normally manifest in some intermittant tough starting or rougher running rather than just stop working outright. Hence back to that little carbon button. I think the part number is 140567, it is not listed in the various parts diagrams out there, but the typical excellent suppliers like Ricambi and AW Italian would have the carbon nub and spring for about $25. My 3.2 items look like this...