Hi mate, you dont have an IAC, you have a TMAP sensor. The guys are probably right with the air leak but you can also check the engine temperature sensor (screwed in the back of the front cylinder head), clean the crankshaft position sensor ( in front of the oil filter). You may have a fault with the TPS also. Had similar issues recently with my SG. Ask me why I prefer Shovels and Evo's!
Can't remove the left side allen bolts in the manifold. I've removed top motor mount and horn for access but though some of my allen keys fit, I can't get enough room for a full 1/6 turn. Time for beer.
It has an IAC.
Good luck Smokey.
I dont reckon you are taking this idling problem seriously steelo.