The catalyst system on that bank has low efficiency, so the catalytic converter may be failing. That is just one possibility (seems like the main one to me), but the thing won’t always last forever. You might check the #2 plug just for fun.
The catalyst system on that bank has low efficiency, so the catalytic converter may be failing. That is just one possibility (seems like the main one to me), but the thing won’t always last forever. You might check the #2 plug just for fun.