Service Engine Soon - Misfire Cyc 1

What is your question?

I was having a problem with the Service Engine Soon Light coming on and when the code was read it said there was a misfire on cylinder 1. I had all my plugs ad plug wires replaced but the code persists to come up. I replaced the coil pack for cyclinder 1 to see if it would fix the problem. The code still persists to set for cyl 1 misfire. The car runs great and I can't tell there is a misfire while driving. What is my next step for repair? Would a dirty fuel injector cause this problem. How do I tell if this is the problem? Jack