Cannot get the P0300 code to go away

Okay, so I have a 02 Tacoma SR5 with the 3.4L. I just did a full motor rebuild and replaced catalytic system along with new O2 Sensors. I still cannot get the P0300 code to go away. The truck runs better then it ever has now and I’m at a lost on what to do. I do know I have none OEM plugs, wires, and coils. I think I will get OEM plugs, coils, and wires and try and fix it.