If you are having to "prime the fuel system" which is what you are doing when turning on the key, and turning it off and then starting the car.
you have a fuel system issue. It was mentioned here earlier......either the fuel pressure regulator or the fuel pump......if it were a leaking injector it would stumble and run rough when it did get started...........same thing with a leaking fuel pressure regulator.
And dont forget the upper plenium will burn through inside the intake and leak coolant into the engine.....starts out as a stumble after sitting a while.
Then it will either hydrolock the engine or die while driving, then hydrolock the engine