okay so i have a y8 block with vitara's and a d15b vtec head (z6) with z6 im and y7 tb aem fuel rail. The problem is my car starts up and idle will bounce from 1000-2000 and very sluggish out of 1st. but i disconnect the iacv and its steady 1500. i have cleaned the iacv i dont have a fitv no vaccuum leaks and coolant is bled. also when the iacv is hooked up it makes a pretty loud hissing noise. any suggestions?

 

Replace the IACV gasket.

 

Like grumblemarc said start with the gasket or run trouble shooting on the iac.I have seen twice were this problem occurred from a bad ect and a map.But these are highly unlikely.You could try the iacv reset procedure since you said you cleaned it.It wouldn't hurt you to check your timing as well,just to rule any improbalizations.Along with cleaning your throttle plate.Hope this helps not confuses you.............Peace

 

thanks for the answers helped rule much out and i found the problem!