I have a 1997 2500 4x4 regular cab with 77500 miles. The problem just started as the outside temperature got above 85 degress. It will not start after it is driven for awhile. Here is the problem. I turn the truck off and then try to start it and it will just turn over and spin. I wait 5 to 10 minutes, turn the key and the engine fires right up. Any chance of fuel line vapor lock?

 

I would get someone to watch the fuel shutdown selenoid when its doing this it may not be opening completly or it could be out of adjustment. If it is opening correctly try loosening the injector lines and see if your getting good fuel spray but be careful when doing this.