[lehiguy]

You can test the IAC by jumping the ALDL like you would to read codes, and holding the key in the run position for about thirty seconds. This will cause the IAC to push all the way in and you will here it making a clicking sound. This is how you set the idle speed by getting the plunger of the IAC all the way in, disconnecting it, than setting the mechanical throttle stop, but it also will let you know if the IAC is working. Be carefull when you replace an IAC. You have to work the plunger all the way in by hand, very slowly or you could ruin it by threading it into the housing with the plunger extended.

One more thought. It can make a world of difference disconnecting the battery and letting the rig sit for a while. This starts things back at default settings and the computer will ignore whatever goofy data it has aquired while you farted around trying to make it run. I went through this very thing on my initial fire-up and I was amazed how much it helped.