AIR METERING VALVE bottom where is?
I misunderstood. I thought you were asking about the missing part - not shown. "bottom plate with hoses to TB".
this is screw ?
That nut and spring ^^ moves a metering valve (not shown) by acting against a "bimetallic spring" in the coolant system end of the IACV. Its fixed (white goop) so as to provide COLD vs HOT idle air volume. It acts on a Bimetallic spring moving as coolant temperature changes.
Bottom far right is a long brass looking plunger (AIR METERING VALVE). Acts against the thumb screw setting Air volume for idle speed.
- I'm not sure what your question is or what you want to know. Details perhaps?