93 Duster 3.0L bucking & stalling

93 Duster 3.0L will intermittently hesitate/buck while underway or stall at idle. When it attempts to stall at idle, sometimes the rpms will temporarily
increase and engine will remain running. Plugs, wires, cap, & rotor were overdue so I replaced those. With key on/off/on/off/on I pulled a code 21,
related to oxygen sensor, replaced that without any effect, code has not returned yet. Ingnition timing wanders or jumps some, when I unplugged coolant temp sensor timing stablilzed, installed a new sensor without effect.

Car has 130k, fuel tank, fuel pump, tank sender, and fuel filter were replaced about 1.5 yr ago. Has anybody had problems with the camshaft sensor in the distributor or the autoshut down relay? Any tips appreciated, thanks. Pulled the top cover off the distrib. The optic wheel looks good, no cracks, warpage, etc.

Car finally acted up enough to set another code. Stalled at idle again, this time would not restart initially. Retrieved a code 11 - no signal from distributor. Replaced entire distributor as Autozone had a remanufactured one for $128.00 The "ignition module" alone would have been $122.00. Was disappointed when I brought the reman home as I opened up top cover and it appeared that electronics were used. Anyway installed reman distributor, set timing and problem appears to be solved. From doing some research, it appears that no signal from distributor/ignition module will also cause autoshutdown relay to deenergize fuel pump.