It sounds like you found the problem. That is grounded to the lower left side of the engine. From experience, the connector that attaches the wire to the engine block fails. Either it falls apart, corrodes, or is loose.
If that ground connector is failing, the next thing that happens is this. You will lose ground/ spark to all coils, and you will have a crank/no start condition. I've seen it too many times. LOL, All the ignition coils share a common ground, and it is the same one. See pic 2.
On the driver's side of the engine approximately six inches from the front and three inches from the bottom of the engine block, you will see a group of black wires bolted to the engine. The last one I did was on a 6.0L, and I had to find it by feeling my way rather than just looking. Interestingly, I had a ground until a load was placed on the ground, then the connection was lost. I fixed the ground and the vehicle started perfectly.
Let me know what you find or if I can help in any way. Note: I would recommend paying attention to that ground to prevent future problems.
Take care of yourself,
See pics below.
Images (Click to enlarge)
Tuesday, April 19th, 2022 AT 7:27 PM