It could be a number of things. When it cranks and doesn't restart, check to see if there is spark to the plugs. It could be a problem related to the crankshaft position sensor.
Take a look through this link and see if anything mirrors what you experience:
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor
Next, is it possible for you to record it cranking so I can hear it?
Let me know. If you suspect the sensor, you can check to see if there is spark to the plugs or if your helper has a live data scan tool, he can check to see if there is an RPM signal.
Let me know.
Joe
Thursday, December 24th, 2020 AT 7:47 PM