The first place I would check is the battery. Make sure the battery is good, and check the connectors. It is critical you remove the connectors and clean them, just "looking" is useless.
The second thing I would do is check the grounds. I would start with the ones attached to the strut towers.
Thirdly, I would clean the pin connectors to the ECM. The ground pin might be corroded or jumping over to a powered pin.
The only thing that makes sense is that you have a bad ground, or maybe some water in a component.
You could also start pulling fuses, and you might be able to isolate the bad actor.
Unfortunately this is the kind of issue that just takes time and a little luck to find.
The second thing I would do is check the grounds. I would start with the ones attached to the strut towers.
Thirdly, I would clean the pin connectors to the ECM. The ground pin might be corroded or jumping over to a powered pin.
The only thing that makes sense is that you have a bad ground, or maybe some water in a component.
You could also start pulling fuses, and you might be able to isolate the bad actor.
Unfortunately this is the kind of issue that just takes time and a little luck to find.
