Car Tech: Help, my car has starting problems in the hot weather

Help, my car has starting problems in the hot weather

Help, the summer is here and my 94 4.0 6 cyc.Grand Cherokee has a starting problem when it gets hot outside. A short scenario, my jeep runs great never any problems until the summer and warm weather arrives. I can drive it to a few places in the morning stopping and starting with no problem but then maybe later in the day say I go to a store park come back out 20 minutes later turn on the ignition and it will not start. The ignition will keep cranking but it will not start. If I pop open the hood to the engine, open the doors and wait 10 minutes it will start every time. But this is very irritating and frustrating to deal with. I have had it to the Jeep dealership 3 times for this problem and of course by the time they get around to looking at it the car will start. If anybody out there has any suggestions to offer I would be very grateful since this has been a couple of years dealing with this.
Thanks so much Kattykay