-1 for putting it on at PGASA, the last thing they wanna do down there is diagnose your problem when they are whipping through 50 cars on the day..
Take it down to Aussie Dyno on corner of port rd and south rd, or boostworx (youll have to book in) boothby st panorama.
if the afm is on, and it idles shit, then he takes it off, and it idles, well, better, my money is on the afm. maybe borrow someones working afm and see if that works all connected?
yeh as craig said, and could be intercooler piping. check all your piping, make sure its all connected tightly, and check that the silicone joiners aren't cracked, hey Craig