rpm rises in neutral then slowly goes down

[davidalindsey]

Whenever I put the car in neutral coming to a stop, the RPM will stay steady then when i am at a complete stop it rise and slowly goes down to my target RPM of 850.
Kinda hard to descibe so I have made a few videos showing whats happening.

Coming to a stop and stoped............................................................................................................start up
<iframe width="560" height="345" src="http://www.youtube.com/embed/3O86adkiXIE" frameborder="0" allowfullscreen></iframe> <iframe width="560" height="345" src="http://www.youtube.com/embed/sEoxJQ58DO0" frameborder="0" allowfullscreen></iframe>

I have also attached a Evoscan log
here: 2shared.com, open it in excel.
And ideals on what is causing this would be greatly appreciated.

 

[Dhan]

It almost looks like the beginning stages of some kind of idle surge, outlined here Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

Like it's an a/f mixture problem and the ecu is trying to compensate for something.

 

[davidalindsey]

Oh and this started hapening after I seafomed the car to check for exaust leaks.
I reinstalled my turbo and exhast manifold due to snapping bolts. No exhaust leaks were found.
I have IAC vaules in my log

 

[davidalindsey]

Bump for any more help.
I installed another iac and it helped alittle bit.

Sent from my Inspire 4G using Tapatalk

 

[phunny]

Have you done a boost leak test yet or no?

 

[davidalindsey]

Yes, soap and water.
I could not find any.
I hear a faint hissing near the throttle body but could not find it.
Im sure its air passing thru the butterfly plate.