97 GT PI swap, comp cams, tuned, etc... Everything including the fuel pump and injectors is new. When I drive the car for awhile and it gets close to operating temp, I will shut it off. I get in it an hour or two afterwards, and it almost seems like its not getting fuel for about 30 seconds. Runs funny almost studders if I rev it a little, but then it drives perfectly fine once warmed up a little. I am thinking fuel pressure regulator? It is the only thing I can think of that would be causing this issue. It has done this before and after the engine swap. But I was also looking at my fuel rail and it looks as if the fuel rail and pressure regulator are all one piece. There is no way to remove the stock regulator, but they sell a motorcraft regulator at O'Reilly's.