Well i took my HHR to my dealers today and showed them when i would step in certian spots on the floor my stereo would make loud crackleing poppin sounds and even with the ignition off i could make it happen!! So they pulled the carpet back and found that the main power supply cable for the stereo and the speaker wire drivers door were entangled and was causeing the problem (interferance) they rerouted them (untangled) and now i hve no more issuse with it !!!! I have heard many others make the same claims so get them to the dealers and make them fix it!!!!

 

Thanks for the follow-up big guy!!