Truck running rough

[Woody7.3]

I have an early 99 f250 6 spd. When i start the truck up, the ses light is on but the truck runs fine. About 2 minutes of driving, the ses light goes off and the truck dies for a second then starts back up. whenever the ses light is off it idles rough and rpm's slightly go up and down by itself. I have no idea what it could be so any help will be appreciated. Thanks.