When points have set for a long time, they get corroded enough not to contact. Some fine sand paper, or a itty bitty file will do wonders. My car had that factory EBZA installed. The circuit boards have been known to heat up where the resistors sit, and run weird. There is a modern EBZA unit, but I am running EZ-2 (only installs on engine, no other stuff controls it). What drives me nuts though, is it can only be adjusted for the 1st cylinder... #2 fires .005 late. Runs well enough to go down the interstate either way. I'm just loosing some free Hp ! So far this new simple ignition has made the car very reliable. It runs the same no matter what. For me, no matter the vehicle, condition, and the age- it should be dependable. At any moment you should be able to hop in, and drive a few 100 miles. If not, make it so you can. This is why I fix everything necessary(up front) when dealing with a older car. A lot of times crap that's been sitting will nickle and dime you to death. Better to straighten them out, before a serious break down in the middle of nowhere... Id much rather have a great running, and driving vehicle- versus a pretty one. My problem is with every new old to me car, it must be even screwier than the last. "Always trying to out do me self!".