Ok, 1991 Mustang 2.3l 8-plug. I am having misfire issues and I am trying to diagnose the issues, but through my research only brings up more questions. First of all, I've heard that one coil pack works as primary, and the other for secondary for the waste spark, but that really doesn't make much sense. I would think that the one post on one pack would be primary and the opposing post would be for the waste spark on the same pack. Secondly, which side is primary, if any, because I would think that the plugs on the intake side would be the primary plugs, to be able to burn the air/fuel faster. And on that note, my mustang has all 4 intake plugs on one coil pack, and the exaust plugs on the other pack. If each pack has 2 primary and 2 waste sparks, then this would not be right (two firing on intake and two firing on exaust side of head). Is my car miswired? Or is my idea of one pack producing waste and primary sparks at the same time wrong? Any insight would be great. All the info that I've read on the internet is very contridicting to the same stuff I've read on other sites. If anyone knows the real answers about this dis system, please reply. I wish I had bought a '90 with a regular distributor, it's so much simpler. Thanks y'all!!!