I have my Wide band sensor located in the slip collector on my mustang, the headers came equipped with the O2 bung already installed. I ran this all last year. After getting car back together this past weekend and running, I noticed that exhaust is leaking out at the slip fit of the collector to header pipes. What major effects can this cause the actual A/F readings. and would it be better to install a bung in a single header tube as close to the collector as possible.........what is the best and accurate way to go?