Assuming you have an adjustable rotor, make sure it has not slipped. Had this happen to me 2 weeks ago at sunset in a not so good area. I had installed the distributor about a month before that.. I had marked the alignment with a sharpie so lining it back up was easy. When it started acting up it ran a little rough and then ran like absolute crap, tried to limp it home, didn't make it. Had it towed home, took me all of 15 min to find the issue. I forgot to locktite the adjustable screw on the rotor.
Also, my previous problem with the ready to run distributor was the fuel line ran too close to the headers and would boil the fuel. Rerouted and insulated the fuel lines
Also, my previous problem with the ready to run distributor was the fuel line ran too close to the headers and would boil the fuel. Rerouted and insulated the fuel lines