I have a Lincoln with a 3.9 V8. It started running ruff and the engine light came on. I checked the code and it was "misfire cylinder 6" So i changed all the plugs, put a new coil on 6 and had the computer reset. The car ran smoother and is getting better MPG. The car still has a slight miss to it. The light came back on and I'm getting the same code "miss fire cylinder 6". I don't know what else to change that would cause a misfire on the same cylinder