Any you good people run into this problem?
The issue started this past winter (michigan). On Decel only there is a noise that sounds like a train whistle in the distance. If you hold the throttle open (i.e. brake torque) when stopping the noise is not present. If you even slightly touch the throttle the noise temporarily ceases. With the coming of spring and higher temps, the noise has started to continue at idle also but it then sounds like a "coke bottle" type whistle.
I have blocked off all vacuum sources for the brake booster, canister purge, PCV etc..... Have also replaced the upper intake with new.
Any thoughts would be appreciated.