Over the last 6 weeks or so, I have had a rough running when cold problem. I did not bother with my breakout box / multimeter / oscilloscope thinking it was a sticking AAV. The symptom persisted with a rebuilt AAV so I had to dig further. In retrospect, one clue to the problem was a worsening symptom - car would not run well after it warmed up.
I pulled my distributor and found a badly soaked pulse generator (trigger points). The lower pair was so oil soaked, I could see a liquid film when I manually opened the contacts. I installed a working spare, installed the distributor, reset the timing and the problem is gone. I think the lower distributor bearing is worn to a point where oil is weeping into the cavity where the trigger points live. It could also be that I did not use the right kind of grease on the cam pads. I need to find a better product for this.
A little research on https://oldtimer.tips/en/d-jetronic/tc
tells me these trigger points are the latest in the production series and include plastic shields to protect the contacts. I had never disassembled these before so I thought I'd give it a try and document what I learned. Disassembly is necessary in order to clean the lower pair of contacts.
First step is to de-solder the wires from the connector; necessary to remove the connector and gain access to the two Phillips head screws that hold the trigger mount plate to the body of the assembly.
I had to walk the connector body out of the slot prying at both sides
Next, remove the screws and carefully lift the plate from the body. If you hold the assembly with your fingers around the leaf springs, it is easy to wiggle it up and off the body. The wires from the lower pair are routed through the large hole in the plate.
At this point, use a pick to remove the circlip and fiber washer that holds down each rubbing block and plastic cover. I had to use the pick to lift the plastic cover off the adjustment tabs because they fit pretty tight - easy to break these if you don't lift them straight up from both ends.
Right lower side clean, left lower side next . . .
I used Norbert's adjustment tool to set the gap at .5mm or .02". I experimented doing this with and without the plastic covers in place. There is a little play in the plate mount. Research taught me to push the plate as far towards the curved piece then tighten the screws. Any gap adjustment done before mounting will require readjustment after mounting so might as well assemble everything then make gap adjustments at the end. I used a small bent needle nose pliers pushed up against the plastic cover - careful not to break what you just cleaned.
Finally, slide the connector back into place and solder the wires. Be careful not to let the solder iron touch the connector body like I did (upper right). I will look for a product to replace the rectangular seal on these trigger points
If this symptom repeats, I will look for oil on the replacement trigger points installed in my car, install this set in a spare distributor and send the leaking distributor out for a rebuild by Cardone.