Here's a new one. Daughter driving my '95 4.9l and the truck "died." A puff of smoke from the right front hood area sent her bailing out of the truck after it rolled to a stop. I get there and the negative battery post is melted off at the top of the battery and the positive cable insulation shows some evidence of heat as well. I haven't had time to look for worn cables yet - any thoughts?

 

I realize it's been 8 years since you posted this, but I just had the exact same thing happen with my Expedition. Electrical problems aren't my strong suit. Do you recall what caused the problem?

 

I would say it was a loose cable connection or a very dirty one...