I worked as a tech for GM in the 90's, and we replaced plug wires more than anything else for cylinder misses. What you can do without a scope, is take a 12volt test light probe $5, and ground the clamp on ground somewhere, and jab the pointy edge in the plug wires one at a time, at the coil pack . Jab right thru the rubber boots on the plug wires, it'll kill one cylinder at a time, until the one it doesn't effect, and that's your missing cylinder. It then could be the plug,wire, or injector. Mostly the wires from my experience though, plugs usually last longer than the wires from what I've seen.
