Just a comment on a problem my wife's Tahoe had that drove me nuts for a couple of months. Her Tahoe would just quit while slowing down for a stop light or sign. It would not crank the first or second time you tried to restart it, but it eventually would. We have an alarm system on it that controls the door locks and a starter interupt. When it would quit the door locks would go up and down and the alarm would arm-disarm. Then the starter interupt would kick in and would not allow a restart until the alarm had been reset. Naturally I suspected the alarm system, and disconnected it as a test. My wife took of in the Tahoe and about 10 minutes later called me on her cell phone to tell me it died again, but restarted. I have to add that I never witnessed the problem. Well one Sunday morning as we were leaving for churh we got in the Tahoe and it was completely dead, nothing worked, no lights, nothing. I left the key in the on position and pulled the hood release. When I pulled the hood release everything started working. I raised the hood and started looking for something. Finding nothing glaringly wrong, I slammed the hood down and everything quit again. What it turned out to be was, the Tahoe has two positive battery cables on the positive battery post. They are stacked on top of each other with a long battery bolt. Tightening the bolt eliminated the problem for about a month. Next time it happend I was driving it. I exited the vehicle, raised the hood and giggled the positive battery cable, restarted and drove home. Upon completely removing the two positive battery cables I discovered a large abount of corrosion between the two cable ends were they layed on top of each other. I completely cleaned the contact points and reassembled the cables to the battery. It has been fine ever since.
I'm not saying this is your problem, just saying don't take it for granted that your cables are OK and you have a good contact at the battery. Check it closely and take nothing for granted.