Stalling engine

If you just touch the gas will it stay running? It sounds like a dirty throttle body and idle air control.
Go to a parts store and get a can of throttle body cleaner. Remove the air duct that comes from the MAF sensor from the throttle body. Spray a small amount of cleaner in the throttle body. Now open the throttle blade wide open and block it so it cannot close. Spray some cleaner on a paper towel or swab and clean off the throttle blade edges and faces. Now clean out the throttle body itself the same way.
The picture is not the same part you have but it's probably as dirty as what you have.
That is carbon, dirt, fuel build up. Clean that off and it should help a lot.

There are tons of videos on youtube showing the basic process of cleaning the system if you wish to look. Just try to stay with GM units as your car uses a pintle style IAC like the second picture. It comes off with two torx screws and you can remove it and clean out the ports the same way as the throttle body.