I was coming back from camp ground in my earley 99 super duty 7.3 auto,not pulling anything and about 4 miles into my trip the service engine light came on and the truck started missing and blowing smoke. It done it for about 40 miles home then I turned it off and about 5 min later I hooked scanner up and it said no codes. I then started it up and there was no service engine light and it had no miss. I drove it about 4 miles and it ran perfect. So I don't know what happened.