[FredG]

Does it start right up after staling or do you have to crank it to clear any flooded gas. Also, does it do it every time under the conditions you listed in your original post or intermittently. I would look at the wiring for a break or loose connection. I had a similar issue a year ago. Drove me nuts for a couple months. Turns out it was a broken wire in the magnetic pickup. Pickup tested fine with ohm meter till I wiggled it. Wiggling every wire I could get access to with the car running would be my first move.
Good luck

Fred