I had a similar problem. The engine would buck a bit like it was running out of gas and a couple of times it died on the freeway. I tried every thing thinking it was fuel related, changed the filters, changed the fuel pump, measured the metering rod, bought new manifold gaskets....I was getting ready to change back to points to test the Petronix and then I noticed that the insulation on wire going to the sensor was very close to the distributor shaft and had worn through. I was intermittently grounding out. I had pulled on the wire while wiping the engine off for a show and pulled it up against the distributor shaft.