check ALL your wires, AND grounds.

you have a bad connection/loose splice/connector, or a bad ground somewhere, and it's showing up intermittently.

electrical gremlins suck. I hate them. I've had MANY rear their ugly heads and stump me for a few days, then I find what it was, and felt like such an idiot because it was always something so simple.

one time I had a no-charge issue, but everything would start up and run just fine. poor connection on my body to negative terminal, but the block had enough of a ground to run the lights, motor, etc. but the Voltage regulator wasn't happy and didn't tell the alternator to charge. another time, i had a no start for a few days. troubleshot it down to a bad coil.

swapped coils, still no start! I was frustrated! walked away and came back the next day. that's when I discovered a bad connection on the positive wire feeding the coil. the terminal was there and holding onto the wire so it appeared to be normal, but the copper strands had lost contact with the crimp somehow. new terminal spliced on, and it fired right up!!