My old school approach I'd like to share is. Before you assume you think you know what it might be apply basic troubleshooting first.
Compression , Spark , fuel delivery. It is a reasonable quick systematic approach. Pull plugs, Compression test. While plugs are out spin and check spark. I prefer stevens instruments 8 cylinder spark tester. Allows you to check all at once. Plus you can check for color and consistency of spark . Shows patterns . For example 1 an 4 , 2 and 5 3and 6, act in pairs. A group in the is showing and issue it points toward trigger. A weak side could be a stator issue or switch box on those systems. You quickly test other things too. Like unplug main harness. Loosen, wiggle and secure all coil plate grounds. Check fuel delivery starting with primer bulb. Do any vents weep fuel?

I give little attention to OHM values. really only pay attention to opens and shorts. Confirm with DVA or some other form of confirmation.

If nothing shows there move to ramp under load test while still on trailer. CHeck bulb while under load. Check timing with load. Timing tends to jump around at free idle anyway. Check spark on each cylinder with light under load.

In most cases you will have a specific direction to proceed. Assuming and bouncing from some suspected problem to suggestion can send you chasing your tail.

I hope you find this helpful