90 Turbo Cold Start Problem

I have a 1990 Grand Prix Turbo, when you first start it up, it keeps dying until it is warmed up by holding down the throttle, even warmed up it still runs like shit. I have replaced the IAC,TPS,FUEL PUMP, FUEL FILTER, ECM, and COOLANT TEMP SENSOR. PLEASE GIVE ME SOME IDEAS, OR I WILL SET THIS CAR AFIRE AND ROLL IT DOWN A HILL.