I had a stalling/starting problem with my '96 Tahoe about 5 years ago. It was intermittent just like your problem. Took me forever to figure it out.
My problem was the wire that goes from the alternator to the engine block. Check the connection at the engine block. It should be at the front of the motor. It's just a nut on a stud that pins the wire to the block (or head maybe I'm not 100% sure). The nut somehow backed itself off and the terminal at the end of the alternator wire was just hanging loose on the stud. I tightened it down and problem ceased. If the connection looks secure check that entire wire for continuity.
What I noticed about mine was that the whenever my truck wouldn't start, the little orange shift indicator lights would be dead also. But the rest of the electrical system (dome lights/door locks/radio) would turn on just fine. There was nothing wrong with my battery. Is that what your 'burb does?