99 6X6 500 dies when warm

My 99 ranger 6X6 500 will start and run fine for 10 or 15 minutes or about a mile and then the engine slows and dies and will not restart until it sits for awhile. This morning I had to walk a mile back home and hook up a trailer to go get it and by the time I got back it would start again and I was able to back it onto the trailer. This happened to me a time or two last year and I remember that the cooling fan came on when it died then. This is the first time recently, although I hadn't used it for awhile, and this time the fan did not come on, but the engine just died almost as if it ran out of gas.

It seems to happen in warm weather when the engine gets warm but not necessarily hot, and otherwise it starts and idles OK but just doesn't run very long. Where should I look first? Fuel filter? Fuel Pump? Ignition? Any suggestions will be appreciated.