today i've been hearing a weird knocking sound when i let go of the gas. I have no idea what it might be. THe only possibility i can think of is my aem cai since the mounting bracket is missing and it might be banging against something. however, how would the aem cai make a sound under the car? any ideas?

 

prolly when it vibrates on the ac lines.. i use to hear that alot.. still i shoved a piece of napkin i thikn on the side of it.. but that was during idle tho