Test Number 2)

Checks IAC movement quality from step 1). Between 700-1500 RPM, engine speed should change smoothly with each flash of tester light in both extend and retract. If IAC valve is retracted beyond control range (about 1500 RPM), many flashes in extend position may occur before engine speed begins to drop. This is normal on certain engines. Fully extending IAC may cause engine to stall. This may be normal.