I logged a run which was not as good as I would like it to be and I was wondering how much an exhause leak(very bad I might add) #7 cyl between the head and header would affect performance and the AFR reading? WOT AFR was 12.3, I havn't tried to do any tuning because I wanted to try it without the blown gasket.
Any thoughts?
Thanks guys.

 

Maybe, you could have been sucking clean air in through the leak.

 

Thanks for the reply, The leak is fixed I was just wondering what affect it would have on the o2 sensor.