So guys I am a bit puzzled as to what is causing this annoying tapping rattling noise in the rear passenger area suspension Its driving me nuts. The recent mods have been a 25 mm sway bar and rear control arms. The troubleshooting Ive done has confirmed it is not related to the sway bar. That is perfectly installed no issues. I believe I have narrowed it down to the rear control arm on that side after reading various forums with people having the same issue after that mod. Has anyone experienced this? And if so what was the solution? It appears to be tightened but I am wondering if it is loosening

I have to get this resolved because the noise is driving me cray cray.

 

I know this will sound ridiculous and I only say it because this issue happened to me. Had a noise coming from the rear drivers side. Rattling. Tapping. Drove me insane. Convinced myself it was a suspension issue. Until I opened the boot and noticed a loose tool in the cargo area. A few months later I get a new rattling noise. The rear seat belt buckle was between the plastic panels and the seat.
Just saying that there's a lot of plastic in these cars and it's worth eliminating as a cause. Especially if its handling fine and it's not throwing a codes.

 

I had the same knock and it was from the thicker rear sway bar striking the frame. I bought the bar from VIP Customs and they sent me spacers to install between the bar and the mount c clamps immediately after I emailed them. Took care of it immediately, no more rattle.