Engine died, Battery / alt problem?
So I was cruising down the road, engine runnin good then it just shut off and wouldnt start back. Starter spins and I have 21.3V in batt. I am getting fuel and accelerator pump is squirting, I have no spark. So even though I had 12V I tried jumping it off with another vehicle and got my gauge up to around 14V and turned the key, it started. I tested the hot wire to my coil and it drops to 9V while cranking without a jump.
I thought maybe my battery was bad and had voltage but not sufficient amps. I took it to work today and out the load tester on it and it passed. When its running the alternator charges 14.2. If I charge the battery for a while it will start the engine. So I was leaning toward a battery problem but that dosent explain why it died while it was running cuz I tried disconnecting the batt while it was running and the alt kept it alive. So Im a little confused.