The IAA valve assembly is located on the passenger side of the motor down
below and behind the intake manifold. It's about 8" from the firewall.
According to the Nissan shop manual, to adjust the IAA valve, disconnect
the throttle sensor harness connector with the motor shut off. Now with the
engine idling in neutral, adjust the IAA for an idle speed of 650 RPM. With
the motor shut off, reconnect the harness connector. Now with the motor
idling, you should have an idle speed of 700 RPM. If you can't get the
proper idle speed, the AAC valve may be defective as It's the one that
receives signals from the ECU. The AAC bolts on to the IAA.
Hope this helps.