Good luck man. I can feel your frustration from here. I hope you get it sorted soon. Just a thought. Have you checked the connection on the coils? Many have had problems with those to the point some have soldered the connection. Let us know what it ends up being?
So....
Turn of the key (initial prime) I’m getting 24 lbs of pressure, 9 times out of 10.
1 time out of 10 it jumped to 52 lbs. and within 30 seconds had dropped to 28 psi.