i just installed my 4-2-1 5 zigen headers. when i went for a test drive, i heard hissing sound. is this my cold air intake because i have more air going in to my motor now or do i have a leak??

or is it normal when you have headers and cai??

 

sounds like an exhaust leak to me. don't worry, i have one, too.

 

oh mother of biscuit!!! now i will have to jack up the car and fix it... this sucks. but i do notice power in the high end

 

no need to fix it, ppl will think you're boosting!

 

If you listen for a little sputter/popin noise at idle and light throttle at a dead stop coming from under the car and you hear it it is in the header (unless you had your exhaust recently changed.