All signs point to IAC, but its not!

[BigPonyMan]

Well I thought my IAC was going out on me again because I was getting all the same signs as I did last time it died (car starts, rpms go up as normal, but instead of stopping at idle speed rpm's fall until the car cuts off). How do I know its not the IAC? Because I just replaced it yesterday. Now I did just have a MAC PC (catless) and A/T c/b installed about a month ago. Could this have something to do with it? What else could cause the car to not idle and just die like that? Any help is appreciated.

 

[stangman]

the next spot i'd look would be the maf. unless you've washed your engine lately then it'll be something completely different

 

[BuffaloZone]

Well I thought my IAC was going out on me again because I was getting all the same signs as I did last time it died (car starts, rpms go up as normal, but instead of stopping at idle speed rpm's fall until the car cuts off). How do I know its not the IAC? Because I just replaced it yesterday. Now I did just have a MAC PC (catless) and A/T c/b installed about a month ago. Could this have something to do with it? What else could cause the car to not idle and just die like that? Any help is appreciated.

Have you reset the computer? Remove the negative battery cable for a few minutes and see what happens. My mom's 2001 Explorer does that about once a year...runs rough and won't idle. I clear the computer each time and it fixes it for another year or so.