Well if it's a whistle. . . .and not a growl. . .it's HAPPY
if it were a growl it would be sad
I know. . .but I couldn't resist!!
Mine does the same whether at idle or going down the road. . .it took me awhile, but I got used to it and kinda like it. I could find no vaccume leak. . . .what BAK
do you have? I have the Kury
. . . just wondering if it was the BAK sucking air.