Jumping Tac, and bucking engine Options

[ThinAir]

For awhile now I've had an occasional "buck" when driving at steady speed. The engine just hesitates and then goes right back to running just fine so I haven't been able to pin down what is going on.

Don't know if it's related or not, but this morning after driving for about 20 minutes, suddenly the engine is bucking like crazy as I try to accelerate from a stop. I pull over and the engine dies, but starts right up again. When I try to go, it dies again. Finally it works on the 3rd try, but as I'm driving I notice that the tac needle is jumping all over the place even when the engine isn't bucking and it continues to buck intermittently.

Normally I would suspect points, but I'm running a Pertronics Ignitor that has been working fine since I put it in back in May. I've run these units in 5 different Type 1 or 4 air cooled engines and never had a problem. Has mine suddenly gone bad or am I looking for something else? All the connections to the coil & injector triggers seem nice and tight.