my V6 CTS has a flutter type noise any time I decal. It is not present at idle or at cruise. I have disconnected almost all of the vacuum systems to no avail. Any ideas? I have thought maybe the throttle body blades flutter at the closed position. Any help would be appreciated. racerjim

 

I have drilled tiny 1/8 inch holes in both throttle blades. My first road test revealed no more flutter noise. It appears problem solved !!

 

Well I am wrong. The flutter is back. Help Please. racerjim

 

I have found that the "dirty PCV hose" that I believe has a check valve in it flutters on decel. I removed it and road tested it, NO MORE FLUTTER NOISE I will try to find a replacement hose assy and move on to other things. I hope this may help others that have a similar noise.