1994 Thunderbird Idle problem

I have a 1994 4.6 thunderbird that i am having trouble with the idle. When i first crank it up in the morning it dosent want to idle, If i can get it to idle it will idle at like 400 until it gets warmed up and then it will be fine. I have replaced the IAC valve already and it didnt make a difference. To give you some history on the car i bought it with a blown motor so i bought a 95 motor and computer and put it in and this is the problem i am having i dont think the problem is related. Any help would be great. Thanks in advance