problem with idle....engine swap???

first off this is my first time posting on this site i got a lot of info on it so i decided to ask about a problem i am having. In the morning and any time i start my car after it has cooled down i will give it a little gas after coming off high idle. Well after doing that the car begins to surge below 1k rpm and sounds like it wants to stall. (sputtering sound). It will do this a few times go back to high idle then idle at normal then i can drive off and the thing runs like a champ. I have no idea what the hell it is i tested the plugs cleaned throttle body, changed fuel filter, i have no air leaks, my fuel injectors all work and it can't be my head gasket because it would do it all the time so i think it is a sensor im just not sure which one. I work at a dealership but none of them can seem to figure it out.

The next thing i would like to know is a motor swap. The new cobalts came out with the supercharger i was wondering if it has a chance of fitting in a 98 cavalier z24...what will and will not line up?
thanks for everyone's help

IAC on your TB. Take that out and hit it with some carb cleaner and in the place where it sits.

I hit it with carb cleaner last night it didn't seem to work it might have made it worse i dunno it seemed a little messed. I'll probably just replace it thanks for the help

When in dount rip the IAT out. :lol2:

Did you just spray carb cleaner into your thorttle body?

I sprayed and cleaned it out with a rag it was alright this morning but it did it again when i left work im just gonna replace the damn thing. Someone in the problems category had the same thing happen and he said he replaced it and it runs good.

You need to actually remove the IAC sensor. Not just spray the TB down and wipe it out IMO.... I am not 100% sure where it sits on the LD9's TB's, but on mine its held in with 2 screws and closest to the Firewall. Spray down the sensor and into his housing.

LOL i know not to spray the whole TB down im not that big of an idiot i found the sensor pulled it out sprayed the housing and and the sensor wiped it out and it still does it