95 Grand Am SE Need help!!!

I have this 95 grand am and it kept over heating immediatley, so we checked it out and it ended up the head was cracked, so we replaced the head, which is hard to get to so we basically replaced everything we took apart just incase.... we replace head, timing chain, all guides, water pump, everything on top..... now the car will not stay idle.... i can start it as long as my foot is on the gas, but as soon as my foot is off the gas pedal it dies.... what is this!? help!

After I put mine back together it wouldn't start unless I kept my foot on the gas, then it wouldn't idle for a while. I kept it running, gradually allowed it to idle by itself, then let it run for 45 minutes or so. All the sensors have to reset, the computer has to reset itself as well. Hope this helps you.