I've been researching the "whistle" sound I hear in my 2004 Yukon
Denali. I found GM Document #1580607 stating the noise comes from "the
same intake manifold design used whether the engine has an electronic
throttle body or a mechanical throttle body". According to GM the
noise is normal and it "may be the result of an airflow disturbance
that can occur as incoming air contacts the unused IAC passage".
Even though GM thinks the noise is normal, it's very loud and annoying
at about 45-50 MPH it is very loud and very annoying.
Does anyone know a work around for this problem?