persistent cylinder 3 misfire?

I've changed the spark plugs and ignition coils on each cylinder. still had cylinder 3 misfire. switched all 4 injectors, still had cylinder 3 misfire. just in case, switched new parts to different cylinders to be sure that cylinder 3 just didn't get a baf part. still had cylinder 3 misfire. The connections to the coils were extremely brittle and likely didn't have a great connection, so i swapped new connector ends on after removing the brittle ones, still had cylinder 3 misfire. swapped ignition coils once again, no change. Now I'm thinking possible bad ground wire to the coil or bad wires to cylinder 3 injector. i checked for power at the coils but failed to check for power at the injectors because i didn't think to at the time. What didn't i consider as a misfire cause? There's no power in that cylinder and i don't know what to do next except take it to the shop. i can't afford that at the moment so I'm throwing a Hail Mary to you guys.