My 2012 Continental GT has failed inspection due to. Rich running condition. It is also very obvious, as it smells very strong unpleasant at idle (almost like an old 70s car).

It seems I have an issue in both banks.

Any suggestions how to tackle this? I plan on getting the MAF reading at idle (should be around 3 gr/s and then do another smoke test).

I will try to get the o2 sensor replaced, but that should not affect mixture during open loop operation, so I am ruling out an issue with the o2 sensors for now..

 

Both banks would suggest something systemic (ie: not injectors or other local issues). The MAF is also bank-specific. What about the MAP sensor? Is there one, or one per bank? Fuel pressure regulator?

Smoke test is always a good idea, but a vacuum leak usually shows as lean running.

 

MAP sensors were measure and are within spec (4.3 gr/s) - in these cars, vacuum leaks result in rich condition.