[rksnc]

You can check IAC resistance if you want. With the lock tab in up position. Measure resistance between a&b - c&d....A starting from right to left with lock tab up. Resistance should be 40-80 ohms
Then you can check from b&c---a&d, resistance should be infinite. Now again that is the connection with flat plug and lock tab pointed up.
You can also turn engine off, ground terminal b, wait 45 seconds ,then disconnect iac, crank engine, if rpms greater than 800 there is a vacuum leak.
With scan tool you could watch iac counts and see better as to what is going on. 0 counts would be vacuum laek, high counts could be from running rich.