Cylinder 4 problems

I have a 2000 ford ranger xlt 4x4 auto 4.0L. I had a problem w/cylinder 4 not firing. I pulled plug and found that the ceramic electrode on bottom of plug had busted off into cylinder. I cleaned out cylinder best that I could and looked into it with a rifle bore scope. I didn't see anything inside. I am hoping it was blown out exhaust port, after replacing all plugs and wires I still feel what seems like a miss while in drive(stopped). I also have a shutter when I leave truck in drive and hold brake and turn steering wheel. Its like the engine is being stained when turning wheel. I have not had this problem before. Any help is greatly appreciated.