As it says I've developed this nasty knocking noise coming from the backend somewhere. Its rhythmic and only happens upon releasing the gas pedal. It will not do it in park, and it occurs in any gear. As soon as I let off the gas it starts to do it, and immediately goes away when I gas it again. It slows down as I slow down and its not affected by braking. Car rides fine, its a 95 GT with 116k. Its an auto and the only mods are cold air, MAC dumps, and electronic shift kit which is almost always off. I did notice that when I let off the gas once the noise kicked up, then stopped as the tranny shifted, and then started again when the tranny was done shifting. Sometime this weekend, I'll lift the car up and put it in drive and see if I can get it to start again while I'm under it. Got any thoughts. I just did the shift kit and dumps and now this noise. Mufflers are tight and the noise isn't random like a shaky exhaust.