Motor running very rough

My motor is running rough. My check engine light is on. I have changed all spark plugs, plug wires, and coil packs. I have double checked to make sure I have the correct firing order. It runs the same as be for I changed all parts. I went to autozone and had a read out. It said originally that cylinder 3 wasn't firing. Cylinder 3 plug when I changed it was the only plug that had dark wet oily look to it. There is no oil or antifreeze smell nor is it expelling any smoke/oil or antifreeze/water out the exhaust. There is no leaking or smell of either liquid when motor is running or otherwise. It is making a ticking noise when running. Thought maybe if I replaced all electrical the roughness and ticking and the cutting out when depressing the gas would stop? It has not. It has changed nothing. The read out from autozone also stated oxygen sensors not reading? Needing to know what the next step in figuring out the problem?