99 Grand Am 3400 wont idle

I put all new gaskets from the cylinder head up started the car and it ran fine, took it for a test drive with no issue. We got back pulled in the driveway and the car stalled and now wont idle. It will run fine with you holding down the gas pedal, when you hold the idle up and put it in gear and take it out of gear it will idle fine. It just wont idle when you start the car. There are no codes at all. Any suggestions as where to look?