Slightly off topic, but I purchased this little gem to replace my 20 year old basic OBD-II code reader. It does everything I need and was pretty reasonably priced...ABS, Air Bags/SRS, transmission info,, real time data, etc. Like it so far, just throwing it out there.
Back on topic:
KatS04, can you keep the motor running with the throttle at all? It doesn't idle, but can you run it at 2k rpm with your right foot for example? When it starts, how does it sound while its running? Is it smooth and sounds normal or does it run rough or anything?
Does the tach work? Not just when running, but does it bounce slightly while cranking? If not, it might be the crankshaft position sensor.
I've had multiple throttle position sensors go out on me, but it looks like you've replaced that already...I'm wondering if you have a wiring harness problem or maybe just a loose/dirty plug. I'd re-examine where you've done work to be sure you put everything back together nice and tight, maybe get some contact spray cleaner and just clean all of the sensor plugs.