Toyota Tacoma troubles

I have been helping my son work on his 2002 toyota tacoma 6cly. The unit started having a miss fire so we had a code reader put on and it said we need to replace injector on 5, we went ahead and replaced all of them, still no help. we then replaced plugs, wires, fuel filter, coil on number 5, mass flow sensor and we are still having issues. today did a code read and getting p1300, o171,o305,o302 and o300. i also changed the new coil to another hole and still get the some reads. What do i do next?