Hard Starting

Hey Guys, Just got my motor finished and in its running good except when i try to start it sometimes. Its hard to get going, well atleast not like it was before. I need to give it a bit on the throttle to get it to fire and run. I was told this is because the injectors are leaking through and fludding the cylinders. The crappy thing is they are new so if thats the case im not impressed. Well any ideas would be apreciated.

Thanks

Yup black smoke is present, On these stangs the ignition timing i believe is controlled by the computer so i would not guess that and the fact that my check engine light has not come on. Hmm Well Keep on looking into it i guess.