I had something similar happen once--the morning was cool, but not cold, and it started and ran just jim dandy. I drove it for about a mile, stopped it, turned it off, and let it sit for 5 minutes. When I restarted it, it died every single time I put it into gear. Restarted and re-attempted to drive it a couple times, finally got her moving, and when I got it up to speed the tranny was making horrific clunking noises when it shifted. Then it was fine, and has been since--no check engine light or anything. I took it in for a once over, but the mechanic had never worked on anything Isuzu and was a little bewildered at best anyways, so I never got a straight answer.