My Chilton manual says "The idle speed on the fuel injected engines is electronically controlled by the Engine Control Module (ECM) computer. The Idle Speed Control (ISC) system electronically oversees the proper idle speed for all operating conditions. This is a good news/bad news arrangement. The bad news is that you can't adjust it; the good news is that it rarely, if ever, needs adjusting. Any roughness or uneven idle is almost due to other causes such as a clogged injector, air leak or loose, corroded terminals in the wiring harness."
Whereas, the Haynes Repair Manual says "if the idle speed is incorrect, remove the rubber plug (if equipped) and turn the idle speed adjusting screw to change it."
Also, when Haynes is covering the Air Valve, it says "to check the operation of the air valve on a V6, start the engine, then turn the idle speed adjusting screw all the way in, while the engine is still cold, rpm should drop; when the engine is warmed up, rpm should not drop." How do I interpret this statement? On my V6, idle can be easily adjusted from 500 to 1200rpm when engine is hot. Does that mean the Air Valve is faulty?