Strange issue

So i have a notorious p0300 code, here is a list of what i have repaired and replaced.

Plugs and plug wires(plugs gapped to .042)
Coil(old one was cracked)
All vacuum lines
Tightened exhaust manifold bolts(4 were finger tight)
One wire on ckp harness was broken at engine harness
Cleaned fuel injectors
Tightened throttle body(2 upper bolts were loose)
Replaced egr valve
Changed timing belt

Now i have found a broken wire on the harness plug that goes to what i think is the knock sensor, compression is 165 across all 4, would that knock sensor wire cause my p0300? Or is it something worse?

The compression on my ''05 is still over 200 after 12 years, so it's puzzling why yours is quite a bit lower. However, I doubt that would be the cause of the misfire, nor would the detached wire. Do you have a vacuum gauge, or an OBD realtime data stream reader?

Obd2 live data, vacuum gauge somewhere

What are the fuel trim readings?

On mine it says frp[psi] and it always states 0.0

My scan tool is a cheaper one that has the fuel trim reading as CL but in the beginning as i fixed all of the issues it was reading OL

A better OBD reader (Torque App, etc.) may be helpful, but here's a few tests to try.

Is the misfire causing a noticeable performance problem? If you can hear it stumbling as you rev it up, then try spraying a SMALL bit of carb cleaner into the intake as it's being revved. If it perks up with the extra fuel added, then a fuel pressure test would be the next step. But if adding extra fuel doesn't help, then check what the the vacuum reading is, and also check the spark with a spark tester.

A chev mechanic may have found the solution, fuel sock on pump is black and clogged

A clogged filter could definitely cause the symptoms you're getting. You might want to investigate what the black stuff is, and try to figure out if there's any more of it still in your gas tank.

Fuel tank is clean, forgot to mention this car sat for about 3 months prior to me getting it, so my guess is that everything sat at the bottom of the tank and when i got it started it sucked into the pump, which would give the black dirt stuff in the pump.