Just did a d15b7/z6 head swap. Changed the IM gasket and Exhaust gasket. Used the y8 head gasket and removed the thickest middle sleeve. Car runs great but the idle bounces b/w 900 and 2000 while at idle. I changed the IACV but no change. Sprayed Carb Cleaner hoping for a vacuum leak, but no luck and no change. The only thing i did not do while i had the head off was to shave and clean the block and head. !!!HELP!!!

 

did you solve the problem yet cause i got the same problem

 

theres another thing under the throttle body take the throttle body off and theres something held on the bottom by 3 10mm bolts... take that off and take the side off thats flat held on by 2 8mm/phlillips head bolts... take that off and there should be a white plunger inside i wish i knew the name of this part i forgot but anyhow that white thing is either loose or completly came off screw it back on... or search for bad idle and ull find information about this if anyone knows how to explain this better tell these ppl cuz i just got done doing this to my friends b7 with a minime and skunk2 manifold and his was idling terrible now its dead on 1 rpm no fluctuation...

 

also be sure your radiator and the reserve bottle is filled completely, i was having same problem and this fixed it.

EDIT: be sure to bleed it too

 

unplug your tps and see if the problem goes away..if it does, then play with your idle screw.