Sorry, I did not read the entire thread, only reacting to the first post.
Something somewhere is not firmly connected.
In my limited experience on this topic, my first reaction is that 22Amps means that a battery terminal is loose - I am sure by now that has been eliminated.
I assume you have already checked that the ground is good and has not corroded.
With all the simple things eliminated then I agree this is a bad connection or a broken wire somewhere.
You might need to check every wire end to end - and if it's intermittent then it's especially challenging.
Three stories, of course only tangentially related, but all related to bad wiring.
My aunt inherited a beautiful 1956 Chrysler in the late '70's.
No seat belts so she had some installed.
Several months later total chaos, turn on the blinker and the brake lights would turn on, etc. - really strange things.
Teenager me gets busy with the voltmeter and starts poking around.
Eventually diagnosed WHERE something was wrong.
Turned our that when they installed the seat belt on the drivers side, they simply drilled a hole in the floor boards and put in a bolt with some fender washers.
They missed a major wiring harness by half an inch when they drilled the hole, but the washer totally covered the harness and squashed it.
Over time the insulation failed and pretty much every wire in that harness was talking to every other wire, and to ground - lots of splices to repair all those damaged wires.
My Nissan once went nuts.
Same as with the example above, a squashed wiring harness.
In that instance the harness ran inside the air intake manifold and when the manifold was installed the harness was squashed and eventually the insulation failed.
That was my error when re-installing it after replacing the fuel injectors.
My very first car, my Austin Marina.
Teenager me falls for labeling hype on a set of ignition cables at K-Mart, "carbon core, ultra low resistance".
Until it gets Wisconsin cold and the carbon core contracts and the carbon breaks internally to the insulation.
And it's intermittent, when it's "warm" or I somehow get the car started, the carbon expands and makes the connection and it runs fine.
When it's "cold" the carbon contracts and breaks the connection, one or more cylinders won't fire and it won't start or if it does it only runs on 2 or 3 cylinders until it warms up.
Good luck on yours, please keep us informed!