I thought they were keyed one way though. They might not maybe my memory is wavering. They do have some adjustment though
I had this trouble on one engine and it was plugs. No idea why it was just a cold day and the slightly gunked plugs wouldn't let it start. Was annoying because it then started no problem after cleaning them and ran on those plugs trouble free for 2 years
I also once didn't plug in a map sensor and it did this.....yea whoops needed that
