Yesterday I had issues with my 91 z28. After I would turn the key to crank the engine it would do nothing for about half a second then crank. It did this several times, then later on it stalled out flat on me while idleing and did not want to start for a minute later (though it would crank). I had no rough idle before that. I'm thinking its an ignition switch problem, but it may also be a VATS problem. What do you guys think?

 

Couple of ideas...pick-up coil in distributor, or ignition module failing under heat soak.

 

I haven't had a problem with it since, but I haven't driven it a significant distance since then. I don't think its the distributor pickup coil since that wouldn't cause the 1/2 second no crank issue. Ignition module under heat soak sounds more and more like the correct diagnosis.