Originally Posted by
avguy
If the required wait is consistent as you describe, that's actually a fortunate thing because it will allow you to at least partially diagnose the problem.
Next time it stalls, immediately connect a spark tester to one of the plugs. In order to do this quickly, you'll need to leave the engine cover removed. You can crank the engine while standing outside, and look through the gap in the bottom of the hood, in order to see if the tester is flashing.
The other test you can do after it stalls is disconnect the intake hose and spray in a small amount of carb cleaner and then crank it over to see if it will try to start on the fluid.
After doing those tests you will be on the way to diagnosing the problem. Fuel would be simpler than spark, but you can also run additional tests with a multimeter if the problem turns out to be spark. My WAG is an electrical/ignition issue, but diagnosis is the only way to go with something like this.