all you need is an intake heat shield, it will block the extra air the fan produces when it turns on, thus pushing extra air into your intake making your air/fuel mixtures all jacked up and thus causing your idle issues, i had the same problems till i got the intake heat/fan shield.

 

Ok, if you want to keep your intake and the problem ONLY happens when you come to a stop and it drops to 600 instead of your regular (?) desired idle, I'm gonna guess 1000, you or your tuner need to increase Desired ISCV Initial Step Position in the 77C and 82C rows by 5 or 6 steps. That will fix your problem.

 

Thanks Guys for all input,ill try that and let Ya all know

 

i hv checked the boost leak but seems no leak .. & also changed the Idle Speed Control motor..
stock TB & yes.. i hv change the aluminum intake & intercooler piping when i swap the engine.
No matter cold condtion or warmed-up idling still floating...

But i knew that when i switch the air cond on/off will interrupt it..