Started to idle rough and had no power?

My car listed above LX started to idle rough and had no power. It began to smoke too. I checked it out with my OBDII tester, and it stated that I had a misfire on my #3 cylinder. I changed my spark plugs and it continued. I then rotated my ignition coils to see if the code changed to the other cylinder. I checked and it continued to read misfire in the #3 cylinder. After each retest, I deleted the code and started over. It is running better, but it isn't right. Where do I go now? Thank you.