GREAT news!
Upon deciding the try and test for what's causing the problem, I unplugged the front 02 sensor in hopes that the car would no longer surge.
IT WORKED!
Car runs GREAT, well, as great as it can be without it's eyes
Anyway, that narrows it down to either a) a bad, brand new 02 sensor, b) a damaged wiring harness, or c) something completely unrelated being broken somewhere else in the car.
I think I'm going to pull the extension out and test all te leads for continuity and make sure it's the harness. Even if I don't find any problems with it, I'll order another anyway, because although I fixed the harness the one time I burned through it, I'd rather have a brand new one I KNOW is fine.