I just installed the AEM COE. I have not even replaced the bumber, but I turned the car on and the this "HISSSES" quite loudly. Is this normal?

Please respond promply so I can put my car back to gether.

Thank you very much.

 

YES...it's all open now. You should hear the air being sucked in.

Once you put the bumper back on, it'll be less dramatic, except when you're laying on the pedal.

 

Are you talking about the Cold Air Intake/CAI? If you are, it hisses enough to hear but not enough to be annoying when the car is cold when you are in the car. You should not be able to hear it unless you really try after the car is warm if you are inside with the windows up. Outside the car you will always hear it. So if the car is warm and you are inside the car with the windows up and it is still loudly hissing then something could be wrong.