2003 Silverado Dies after 100 miles of driving

I have taken my 2003 silverado on a couple of trips over the last 6 months, and both times it died after going over 100 miles. The first time we had it towed to a dealership, and when they got to it the next morning it started right up. They kept it for a day, and could not find any problems.
The second time it died on me, I left it sit for about 45 minutes and it started right up. Dealers cannot find a problem, and I have a fairly new truck that I can only drive to work and back.
Any help would be appreciated.

My factory pass lock system has done that to mme a couple of times on long trips, 500-1000 miles. If i stop at a rest stop it wont start for awile and the security light comes on in the message center, never had it looked at but i have seen tsb's for this prob and it was the security system causiing it. My truckwill start usually after a few minutes. Does your truck act like it wants to start but then dies as soon as a cylinder catches. If so you may be having my prob...jj

buy one of those cans of compressed air you use to clean your keyboard with, when it dies, spray the cold air inside the switch or around the switch, see if it starts up...