My '93 f150 5.0,4X4, auto. 107,000 miles was running fine as usual, shut it off for an hour while in a store, come back out to fire it up, and it began idling rough, check eng. light came on and off and it stalled. Fired it up again and same thing. I limped back home with it stalling and bucking while driving and having to restart it while rolling down the road. I've never had any trouble with this truck in 10 years, what gives?