ok so i have a boosted b20 that originally had an ls head on it. i jus switched over to a b16 head now when i start the car i have a high pitched whistle...(vacumm leak) and i found that it is coming from the iac valve. thats where the noise is the loudest and i sprayed all the vacumm areas with carb cleaner and when i spray the area that the iac meets the IM the tone changes noticably. i switched iac valves with an extra i had around and the tone got worse.. im out of ideas can anyone help please!!!!

 

do you have the proper o-ring to seal the iacv to the IM? thats really the only place it can leak