I have a couple of thoughts. First I noticed you are in Florida. As the temperatures are nearly the same as the rest of the country went through several months ago without issues I would rule out basic fueling issues. ( calibration scheduling ). That means it is vehicle specific as most GTO are starting fine. One thing to look at is fuel. You are in Florida where temperatures are higher than normal. Winter fuel abounds. Higher RVP fuel ( especially Premium fuel ) in warm weather can be a problem. As a point of information, all fuels are rated not just for RVP and octane but many others aspects. One meteric they are rated for is called "driveablity". How the fuel drives as the engine warms up. All premium fuels ( high octane ) are rated much lower than the lesser octane fuels on this rating scale. You may have a gas stsation selling "Winter" fuel in Florida. Try changing brands. You may be experiencing a slight vapor lock in the fuel line. ( just a few pockets of vapor will cause stalling. Where severe vapor lock occurs in the injectors and it's very hard to start, the fuel line vapors will only cause stalling. The fuel lines do purge every time the fuel pump cycles. ) The second cause could be a bad check valve in the fuel system. When you shut off the engine there is a small check valve in all fuel injected vehicles that keeps pressure in the fuel line. If the pressure is not held or the fuel leaks back alot, the first fuel delivered will be very lean. It is this first "squirt" that really starts the engine. Lack of pressure will cause the problem you are experiencing.
Here is something to try. Before cranking your engine, just turn the key to run, wait 5 sec. turn the key off, and cycle it again, without starting. ( what you have done is purge the line and/or increased the pressure to the controlled pressure. Now start your engine on the thrid try and see if it runs correctly.)... One last thought. A leaking fuel injector can also cause a loss of line pressure. Dealers have a methodology of finding which component causes the pressure loss. So once you have tried my "key cycle" test and your engine starts and runs fine. Tell the service manager what you suspect.
P.S.
sorry it's sooooo loong but, if your engine still starts and stalls the culprit is most likely poor fuel.....Hope this helps to sort it out....