Well I just got it running correct tonight.
PO said it started running like crap after getting gas and going to a car show. On the way home it acted up. He got it home and switched the o2 sensors around and apparently he did a full tune up but never mentioned that part to me.
I got it on my lift and found one of his o2 extensions was shorting the high impedance signal to the ground on that harness. Also checked fuel pressure, injectors and plugs. Car still ran like crap. One O2 was bad, the MAF was bad, MAP sensor had a vacuum leak, motor was sucking air past the MAF and we found a few more questionable wires. I ordered a MadZ28 (Mad Tuner) tune and it ran a bit better... detonation at idle issue went away.
In fact, my buddy had it running long enough to get the SES light to start flashing (telling us it had a misfire) and then it died 15 seconds later. I was about to check the cap & rotor on the opti and as the coolant was draining down I decided to go over the firing order and noticed 5 & 7 were backwards... lmao. It only took me 16 hours to figure out that the final issue was the firing order
Anyway, I did plugs and wires and went to fire it up and it didn't do anything. I checked for spark and didn't have any fuel pressure BUT I head the fuel pump priming. I disconnected the line before the fuel filter and still had nothing happening. I took the pump out (thank god the PO did a fuel pump access hole) and tested it in a bucket of water; pump kicks on and spins but doesn't suck.
Got my new pump and the car is running. Hard for me to pinpoint what my issue was because I feel like it was several things but the main issue was defiantly the shorted O2 sensor, crossed wires and MAF.