Forgot one other thing...sticking or incorrectly set idle micro switch.
Acceleration enrichment module failing.
Where is this at? If the car had a carb, I would say the accelaerator pump is bad.
Same thing, but electronic.....small black thing on side of CISe air meter head.
Otherwise known as a air volume meter sensor. It sends a variable voltage back to the ECm for air flap position.
There's been a post here on it's function and setting some while ago.
http://www.landiss.com/mixture.htm