1999 GT WILL NOT IDLE WITHOUT HELP.OK ABOVE IDLE[:@]

 

Hey, I just had the same exactproblem today. Found some threads here about the IAC and cleaning it. Also found this link which was VERY helpful. Most likely just nead to clean your IAC with some carb cleaner. I did it and itfixed myidle problemimmediately. It is a quick and easy fix and I figured even if it didn't fix the problem it should be done anyway since I have over 100K on my 2000. Here is the link, good luck!!!
http://www.muscularmustangs.com/iac.php