crash2
-Oh no I picked a side-
Intake leak? Honestly putting it on some sort of computer and watching a graph is going to be your best bet. Like everyone else said it's just going to be a guess.
You have to remember what an IAC does--its a controled intake leak so to speak. An intake leak will typicly cause a high idle condition and depending on how large the leak is can cause a lean miss(which is quite common on the 4.8 and 5.3's)