If you look at a 95 EFI electrical manual you will see a condenser between coil +Ve and ground. None of this misfire happened until I put a new 4.0 V8 in. However all the ancillaries were off the old 3.9. The scope picture you show appears to show the coil -Ve signal and looks normal. My system was passing coil firing pulses back on to the +Ve 12 volt supply line. This line should be clean. Whether it is due to my Powersparks Viper dry coil I don’t know. The amplifier, as stated by the other poster, receives its input trigger from the pickup in the distributor. This triggers the amplifier to connect the coil primary to ground. The signal on your scope is that signal. Once the primary signal fires then the secondary part of the coil fires and produces the spark for the plugs. Of course as the coil pulse dies a back emf is generated and this is dissipated without issue. What I have and diminished is that secondary pulse is somehow getting onto the coil supply and causing miss fires. The condenser cured that. I have checked all earths/grounds wiring, shielding and connections and all are good. Grounds are less than 0.005 ohms. I think 2 ohms is too much but a better way would be to try and see what voltage is across the connection. I put a condenser on the alternator just to try it and for no other reason. At least you are on the right path so it’s a matter of eliminating each part.I'll give that a try. Also, a couple other ideas:
1: This is my engine block ground from the coil. I get continuity to the hood mount ground, and the battery ground, so it's not NOT grounded. But I do get maybe resistance, 2Ω maybe... I'm wondering: does this ground from the coil contribute to spark strength? If so, perhaps a new ribbon all around, and clean shiny contacts would be smart.
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2: I read a very interesting snippet in the engine section of the service manual. Trouble shooting EVERYthing, it ends up at the brake servo vacuum line as a check point as it can affect engine performance greatly. I havne't found exactly where it is, but it should be an easy check under the brake pedal and out the firewall. I would guess it's VERY old since I haven't replaced it. So, just another thought.
And, really, these things could possibly all add up.
I do know from long experience that the longer it takes to fix a problem such as this the simpler the cause in the end. Don’t waste your money throwing parts at it.