Hey i have a 2006 cobalt ss 2.4/na. I was driving on the highway when i heard what seemed to be a pop and now i hear this buzzing noise whenever i step on the throttle. it doesnt do it when i am in neutral or let go of the gas. I am just wondering, could that pop have been a vacuum hose line somewhere in the engine popping off and now its just sucking up nothing?

I haven't lost any power or nothing, i just hear this buzzing noise, it sounds almost like its coming from my intake when im driving but im not sure, any tips?

 

Supposedly that could of been ur flex pipe breaking..and now u hear a buzzing/hissing noise right?..my car did that too. Although i did not hear the pop thats what my car dose even today and they supposivly fixed it..quite annoying at one time it was as loud as my supercharger! I think what it is, Is this stupid gasket in the flex pipe thats broken and thats what makes the noise. im getting sick of my noise in my car gonna get and aftermarket pipe..lol

thats what i could be though ur flex pipe, if im wrong anyone please correct me

 

Mine started doing the same thing the other day and its as loud as the blower sometimes

 

well i am getting it check out today, couple of possibilities is it could be a leak some where in the exhaust manifold, could be a flex pipe break or gasket leak like you said or its coming from the exhaust baffle. Oh or it could be a rubber tubing somewhere that is meant for a vacuum seal, i guess we'll find out soon enough

 

Well I took my car in today and sure enough my flex pipe had a massive hole in it and it ruined my cat and my O2 sensor so I'd advise getting it in there asap

 

im on here for the exact same reason. i've been jacking my car up and checking and cant find anything. i had thought it had to do something with my exhaust but it sounds under my passenger side when the windows are close