Ignition problem

My 318 did this for several months before it died completely. A timing light showed the timing mark jumping around which left my dad scratching his head wondering what would cause that. The answer wasn’t long in coming. My engine had nylon teeth molded onto the timing gear. Either the teeth had worn down or the chain had stretched over time. I don’t know which was the case. Either way, the timing chain had developed enough slack that when the starter was engaged the slack was pulled out of one side and added entirely to the other. This caused a misalignment of the crank and cam. The moment I released the starter things fell back into alignment and it fired. I drove the car this way for a few months wondering what was going on, then the timing chain jumped a few teeth, the pistons came up and whacked all the valves, and that was that. My car spent the next thirty years sitting at the end of my parent’s driveway. Put a timing light on your engine and make sure you aren’t having the same problem.