Won't start one day and fires up first crank next day

Simplify this a bit, I have not read threw all the great help here, I have had the same problem, coil would heat up and not start on a truck I had, changed it out an no more problems of not starting
yeah seen that before when hot there is a short in the coil when cool it goes away. presume caused by pressure due to oil movement in the caseing when hot