2005 Jeep Grand Cherokee Laredo car sputtering.

Ok so car starts fine when cold but it seems to not
want to start after driving it about 25 30 minutes.
Let me try to explain what its doing.. You know
when a car overheats and after you shut it off it
wont start until it cools down after 15 minutes... It
seems like this is what its doing except that the
cars not overheating or at least not telling us. So
we drive the car, get on freeway or go across town
to do our everyday stuff, turn car off to go into
grocery store for about 10 minutes, come back out
and try to start car but it wont start, it turns over
just no start. We do this a couple times and
eventually it does start.