Nice work 4stfire! Looks like you're on the right track. You've cleaned and inspected quite a bit there.

 

So as part of my last troubleshooting I did check the connectors in the coil . They looked "OK" but not really easy to reach in their location to clean them.

I inspected and attempted to disassemble the coil harness plug.





Back of coil harness plug.

I pulled the grey rubber grommet out to inspect the terminal connectors and wires inside. These looked "OK" as well but I couldn't find a release tab to get the wire terminals out of the plastic housing.





Coil Harness Plug

In the end all I could guess was that the contact between the coil posts and this connector just wasn't solid. Anytime I wiggled the wires at the connector the engine would stall. There had been another coil installed as part of the shop's troubleshooting attempt and maybe the connection posts on that coil were just a bit bigger and stretched out my connector????

What I did was to install a strip of copper tape into each wire connector in the plug above. This seems to have been enough to fix the continuity problem. I wasn't able to replicate the failure by wiggling the wires and it hasn't stalled or faltered in the last several hundred miles.

At this point I will call it a win. Thanks everyone for the guidance and support!

 

Awesome.