My S4 has developed an annoying knocking noise on the rear passenger side. This is really starting to p@#s me off now, I can't find anything wrong! I'm running FK coilovers, I've replaced all the worn bushes, there's absolutely no movement in the suspension at all, just flew through its MOT, the ARB is perfectly fine, the exhaust isn't catching, there's no worn/shiney marks/dirt rubbed off anywhere, nothing loose in the boot, but still over small bumps/potholes there is something that sounds like its real loose, rattling knockey noise, but at speed/over nice smooth bumps there's nothing. I'm at my whits end, there's nothing left to change that I can find that could be a problem. Anyone have any ideas? Anything at all? The only thing that I can think of is a knackered shock, could this cause it? Even though there's no leaks from the damper, the piston still moves nice and slow in and out like I'd expect and there's no sagging. Help!!!!!