I changed my car cat converter as it was giving PO4020. After driving for 2 weeks I noticed soot mark as shown in the image above. There is no audible leak sound (tapping) at idle and when revving. When driving there is a slightly "hollow" sound at high revs. I do smell some raw exhaust intermittently. However I think some carbon may have sealed up the leak.
I remember that I may have slightly overtightened bolt #2 as my torque wrench was too long to fit in the tight space so I manually adjusted with a normal ratchet with the same "feel".
To fix this, should I loosen #2 and retorque it to spec, or should I just tighten bolt #4? Also should I loosen bolt #4 and retighten or just retighten it right away.
I've used the upper end of the torque range 46Nm so I'm afraid the bolts would break if I tighten too much.