I'm sorry I didn't see this sooner. The first thing I would check is the FC switch in the N/A AFM. Turbo models don't have this and it's usually not suggested, but I've seen them fail for a few people (unfortunately, usually after they'd spent a bunch of money on other things).
http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=95
A couple other possibilities are timing (yup, still a possibility) physical or ignition, TPS IDL switch, fuel pump, fuel pump relay and/or resistor pack, clogged ISC or dead stepper motor in the ISC, bad alternator (try charging the battery and see if the car will idle at least for a while with a full battery), and lastly, a bad ignitor.