ok ok ok, I've heard it all. Vac leak, intake manifold bolts loose, ect. But the fact remains that my 91 YJ, just f*#$ing whistles no matter how tight anything is. the whistling is definetly coming from down the air tub somewhere and i can hear it beacause i have a cone filter (thanks rusty) on the end of it. I think that its a problem with the engineering of the intake itself because it doesnt occure unless I have my foot on the gas a little. I stop it, it stops. I let off the gas it stops. If anyone has any idea on how to get rid of it, please lemmie know.