Truck backfired and stalled out?

For the last few days, I've been having issues with my truck. On Thursday afternoon, the truck back fired and died out. I initially thought I was running out of gas. But even after filling up, the truck has continued to run poor, stuttering and sputtering occasionally. I didn't drive it over the weekend. This morning, it died out twice on the way to work. Once while at a stop light and the second time as I pulled in the driveway at work. It appears that slowly down is when the problems ensue.

Any ideas on where I should start with this problem?