Ok so here's the deal. This started about a week and a half after i finished installing my system. My subs have a low rumble coming out of them ONLY when the car is one. it's very deep. Ifi change some of the settingon the amp they get louder and quieter. It happens when i have my cd player on cd or tuner. not during aux tho...b/c nothing's hooked up there. Im thinking my amp just decided to crap out of me... I've talked with co workers up at circuit city they said it could be a strange engiine noise problem. So i ran a ground wire from the head unit to the ground where my amp is grounded. nothing...still there. I got new rcs's, still there. re wire the subs over and over...still there. Re-did every wiring possible. so i'm left with it either being signal coming from headunit, or something messed up in the amp... so yeah what do you guys think it could be? my system is listed in another post named "whatcha think" .....so now, whatcha think XD gah.