So this is the last (for now) and most frustrating part of my new to me "Perfect" Disco.

P0327

This pending code was unhidden when I hooked my my ultragauge.

After removing the AC I found multiple old fixes in the cable. At this point the cable was too to repair again and keep route the same. Being the noob I am, I rerouted too close to the exhaust manifold and guess, what, it melted.
Traced wire back to the firewall kind of above the intake manifold, bought new cable and rerouted more over to the brake lines and down to the drivers side knock sensor. Took lots of care and soldered and heat shrink. Code seemingly went away for about a week.
P0327 came back!
"genuine" sensors are currently out of stock most places, so this morning, I swapped the drivers and passenger sensors hoping that now that I have the wire sorted that maybe the actual sensor is bad. When I took off the suspected bad sensor, it did appear to be a bit melted and deformed so YAY maybe I'm onto something.
My current theory is that if i have a bad sensor, my P0327 will turn into a P0332 (rave 18-2-43).

 

Today, about 2 weeks after swapping sensors, my theory was proven right when I got a P0332. This proves to me that the sensor itself is bad. It's hard to know which sensor is which and who is selling genuine so I just had the dealer order me one. $110.

Previous owner records show hand written that someone changed the sensor in 2019 for $75 - parts and labor. At that rate they probably threw in a $20 sensor that was used or junk, who knows.