I did get up there this past weekend, and it took another full day, but made some progress. Mixed feelings on it because it isn't a fix, but rather a workaround. Still no idea what the root cause is, but I can move on from here.
I did not wind up needing to run a new shielded wire. I started out the day with grounding the cam sensor to the block. I thought this fixed it straight away, but turns out the gremlin was still there just dramatically reduced in severity. I was immediately able to rev past ~4500 and all the way up to 7400. Funny how fast it gets to the rev limiter when you're used to it cutting ignition at 4500 rpm haha. I did bring it back down and held it steady at different RPM's from 4000 to 4500 and eventually it did start having small misfires. Not the huge RPM dropouts as before - it would stumble and recover faster, and as mentioned it would let me rev past it cleanly on a faster sweep.
Looked at the datalogs and went down a rabbit hole of working on the crank sensor thinking it might be contributing as well. I should've just stuck it out with the cam sensor only. I wound up grounding the crank sensor with no change, fed 12V to the crank sensor with no change, and then fed 12V to the cam sensor and it worked 100%! Dropped the starter for a third time and put the crank sensor back to normal wiring and it again worked fine - reved clean 100%, and I swept RPMs between 4000 and 5000 very slowly for at least 30 seconds and didn't once have a dropout.
The only little annoyance is the engine takes longer to crank now. My theory is that since the cam sensor is hooked to 12V directly when you key the starter the voltage drops and spikes and might be causing some irregularities until the voltage settles out. The switching point on these sensors is only 3.5V so it is 100% getting ENOUGH voltage to switch, but it is just really dirty on that 12V bus when you crank.
To finalize things I need to clean up the wiring and make this a bit more permanent. I don't see any other issues on my other sensors that would give me concern that the harness has other flaws. I don't know the source of the noise in the harness, but I should be good to go. I do have an unused regulated 12V pin from the ECU I can tap into and try that to see if cranking improves. This will likely be how I wrap up this saga and whatever it is, it is.
I do still need to find what the parasitic draw is I have yet to be able to find what is pulling 2 amps with the key off.
So to answer your question the engine feels smooth finally at every RPM, and still sounds awesome lol - especially at 7400 rpm.
