C4 LS1

So I finally get around to trying to start my car after the carb to fuel injection conversion and when I crank it it will only stay running if I give it gas...? It is also posting a MAP code. I have checked for vacuum leaks and could not find any. I thought maybe it was a sticking IACV but thats brand new. As soon as you left off the gas the car dies without hesitation. Does anyone have any idea what might be causing this. I had the PCM tuned by RPM in garner so the vats is removed and all emissions stuff.