Hi all, first time so hope this is correct. I fitted a 3" mandrel bent exhaust with high flow cats about three months ago. On Monday I had my engine light come on and then the trc/ vsc and vsc off lights also come on. I had local mechanism ccheck and he said it is a n O2 sensor fault, due to the exhaust. Can anyone shed some light on why it has taken three months to show up? If it is due to system, is there a way of fixing? Thanks in advance