Let's try to keep this thread on track - we're discussing the idle issue, and the sudden drop in RPM.
I have 1400km on my 6MT FR-S, and have been experiencing the idle drop since the first day I got it. I'm running 94 Octane Chevron fuel (considered the best in my area). I haven't been running the A/C - and I don't believe it's related to accessories.
I notice this the most when coming up to a stop light fast, and when i'm stopped, clutch-in, the rpm drops and comes back a moment later. My first thinking was that it's a new car.. needs to run a bit to smooth out. Now, after seeing the video on how D4-S works, my thinking is that the switch from combustion chamber injection, to intake injection is the culprit here - i.e. the change is overlapping, and so the ecu is cutting fuel so the rpm doesn't surge, or the change is too far apart, and there's a momentary lack of fuel as it switches over (and with the clutch pushed in, there's not the extra momentum of parts spinning...)
The above could definitely be caused by the camshaft being off, or if the exhaust valves timing is affected and the flow through the cylinders is interrupted going from high speed to low.
I'm hesitant to take it to the dealer (as I'm sure everyone is) because I don't want the techs joy riding in my car while they work to figure it out. I'd be much happier to walk in with a TSB and say - I have this, fix it please
That said, I'm going to locate a # for a SCION Canada rep, and will post it here if/when I get it for all the CAD folks to call in.