I just replaced my fuel pump with the 04 focus svt one because my old one was bad. car runs perfectly fine except sometimes on start up. If the car is started up for a couple minutes then turned off it wont start right back up or like 10 mins and when it does I have to hold down the gas to start it up. if the car is warmed up it starts up perfectly fine. I just replaced spark plugs and I am thinking maybe this could be a leaky fuel injector flooding the engine. fuel pump turns on fine as far as I know.