My 75 Porsche with the original D Jet has started to occasionally buck or stop when on the road. Over the years I have replaced the wiring harness, the Maps sensor, voltage regulator, coil, trigger points.. and a few other items. I checked the dwell a month ago and it indicated the points were off, so I changed them. This seemed to solve the problem for a few short trips, however, the issue is now back with a vengeance. I limped home today with numerous events on the interstate when the engine just started to loose power and the reves would drop and if I did not down shift and get the reves to 4000+ or pump the gas the engine would die completely. Thankfully once dead it would start and if I kept the reves high I could drive a bit further. Once home I checked the dwell and it is at 50 which I recall is at the upper range but should not be the culprit. I do not feel vacuum leaks nor any obvious loose connection. Only thing I wonder about is that I noticed that the voltage going from the coil to the points is 6 volts, is this correct ?

Any suggestions as to where to troubleshoot would be appreciated. I will be checking out my fuel filter since I think issues with it could cause the engine to die yet restart easily.

I had a bucking issue on mine that did not go away until I changed the coil.

I had previously changed the engine wire harness and ecu, all new gas lines and filters, got injectors cleaned and cleaned and reclocked TPS.

i agree with Mark this is a possibility, but bucking issue can be caused by a number of things I have had a few of these- bad TPS, FI grounds shorting out or coming loose, or other grounds not making good contact.
Test the coil or wires , and check the tps , just unplug it and see if there is a change or improvement. The last time I had really back bucking it was the worn TPS board, but the time before that was the coil.