Krenath

The IAC for the 2006+ S2000s does not seem to be in the same place as on the earlier years. Where is it?

Is it part of the drive-by-wire assembly?

My 2006 has the shaky idle issue and I've armed myself with carb cleaner in preparation for this simple process only to find blank aluminum where I'd expected to see my IAC.

Krenath

Okay, page 9-3 of the 2000-2007 Service Manual shows me what looks like a complete lack of an Idle Air Control Valve.

If so, what could be causing my shaky idle issue?

It actually idles fine unless I rev the engine. Then it stumbles and recovers.

Carbon Blue

try cleaning your throttle plate in the throttle body (backside of the plate with the car off), mine was completely covered in carbon build up. I cleaned it up and the idle was a whole lot smoother, but s2ks are known to have a quick shake/stumble once rpms reach idle.

Slows2k

DBW cars do not have a separate IAC, it's controlled by the throttle plate. IAC was eliminated by DBW