ROBBIE/AZTEC GOLD

I have a 97' gt and when you start the car you have a rough idle with hardly no throttle response. The car is acting like it's loading up or in other words running rich. I put an Idle Air Control Valve on it and the problem still persist, The IAC may have been some of the problem but it is still doing it. You can unhook the battery, let the computer reset, then you can crank it up , may have to cut it off once then fire it right back up and it runs perfect. After you reset the computer it may go the rest of the day without messing up. If anyone has any idea's of what it may be I would appreciate it