Yet another Idle problem

[SupaFly Skyline]

Hi all, firstly i tried a search, and found similar problems, but mines different. A couple of months ago my car started hunting between 1grand and 2 grand at idle, fixed this by replaceing the AAC Valve. now its started to idle very randomly, sometimes it will idle smoothly at 1000RPM, sometimes smoothly at 2200 RPM, and also anywhere in between 1000-2000RPM, other times it will idle at 2000RPM but "hunt" between say 2000 - 2050 RPM (needle on tacho doesnt move much, buts its rough as all hell). Since this second problem has started, when backing off (cruising to lights) the idle is rough as the revs drop, then (stopped at lights) it will idle where it wants too. In addition to the idleing problem, my Exhaust/Cat convertor over temp light flashes all the time, it mainly comes on under compression, or very light acceleration, i thought maybe my cat was stuffed (or empty maybe) and the exhaust gas was too hot so i removed the exhaust gas temp sensing probe and tied it up under the car in the cool air, but the light still comes on and has a the idle probs.

Atm im strapped for cash, so before i start trying different things that may not be remotely close to fixing the problems (and wasting what limited finances i have), does anyone out there have any ideas or suggestions on how to fix these dramas?

EDIT: the car is an R32 GTSt, with a FMIC, cat back exhaust and about 13psi of boost(rarely see more than 10 though)

[JAPCAB]

Clean your air flow meter with carby cleaner.

[blind_elk]

Try cleaning the AAC valve.

[SupaFly Skyline]

done both, but will try again, not sure what the exhaust gas temp light has to do with it all though?

[rs73]

blocked cat converter?