Stumped......

It sounds like a fuel problem. If it was electrical it would be back firing like when you do a Key job. The new fuel with ethanol boils real fast. Your floats could be set low. The float does not function properly with boiling fuel. I have seen cars flood when restarting hot. Try pulling the sock off of the tube on the sender in the tank . Also do a vacuum test on the pump inlet while cranking it see if it is working properly If you still have this issue . I have another thing you can try