Haha Bro, u're funny.
Well, my problem is abit weird and pretty difficult to replicate.
There will be a knocking sound from the undercarriage whenever i'm suck in a massive jam (causeway jam). After continuously pressing the foot brakes and accelerate at low speed (u know lah ... stop and move .. stop and move) for 1 - 2hrs the knocking will appear.
Then TC says is exhaust cones faulty .. but yesterday I was caught in the jam again, the sound still there but not as loud as previous.