[COBALT]

Ok new twist. They managed to get the tahoe home, and the story is the AAA guy "managed to get it started". It was parked on an incline and he made some comment about how the engine might not be getting the right amount of fuel, because it aparently died. Then he let it coast to level ground and it started right up.

Quite a mystery, but I'm thinking the relays in that relay center (driver's side under the hood) are most likely all experiencing some degree of failure. I checked out the battery and the alternator - they're fine. So, I'm going to replace the fuel pump and starter relays.