I have an 88 firebird with the 2.8l v6, my problem is that when the car is started cold I have to feather the throttle to keep it running and I have to do this for about 5 minutes till it warms up. After it till stay running pretty well there are times when the idle will drop and it almost dies but for the most part after the first 5 minutes it will run well. Does anyone have any suggestions for what I should look at.

We just swapped a used engine into it and so far I have checked the pressure on the fuel pressure regulator and it was about 44psi, I also checked the injectors cold they were around 15.7 and the tps seemed to be good but the idle air needs to be replaced