About a month ago my cel light came on after some hard driving. It started running kinda ruff. After switching the car on and then off the light went out and the car ran fine. It did this a couple times then last night it came on and has stayed on. The car seems to be running fine but i went to autzone and pulled codes. It showed cyl misfires for 4,5,6. Any help to the cause of this would be helpful.