Car won't start most of the time. When it does will only run for few minutes.

It all started with a hesitation about a year ago. Then the end of december it started shutting off at an idle and while driving. Most time I could wait about 20 minutes or so and it would start back up. It may run for a few miles or most of a day. One time I could start it back up right away. That only happened once. I have replaced the fuel pump and relay, automatic shutdown relay, injectors, idle air control, throttle positioning sensor, crankshaft positioning sensor, and the ecm. The ecm and crank sensor were replaced in the last week. The cam sensor is about 2 years old. It would be the oldest. I am losing the ground for the asd relay from the ecm. That is why I thought the ecm was bad. Now it will not run for more than a few minutes then it shuts off and I have no idea when it will start again. It is to the point now that it could be a few days before it starts then it will only run for a few minutes. I have taken out the entire engine wiring harness and fixed every little scrape and cut insulation I could find. Looking for ideas on what to check next.