Still wouldn’t hurt to just go back over everything,and looking at the plugs can sometimes clue you in to any running issues you might have. Little odd problems can be a pain sometimes-but sounds like you’re keeping after it. I’m sure you will find it
Are you losing prime in your fuel system occasionally? Maybe a leaking fuel pressure regulator. Pull the vacuum line off the regulator and see if it spits fuel. Can you tell if it's running rich?