Stall, stop, smoke

I recently replaced the starter on my work van. Today I found the starter bolts loose after trying to start it up. Tightened them up, and my van started right up. drove it half a mile and it stalled. Tried to start it again, and I saw smoke smoke from the tail pipe. I waited a few minutes and tried again. It started up. I then drove it to the job site, and it stalled again as I was parking. What kind of issue could I be dealing with?