Quote Originally Posted by 2xls1 View Post
It's not back pressure that is needed. It is you don't want O2 sensors anywhere close to open exhaust so outside air doesn't effect their reading oxygen only in the exhaust. This means absolutely no exhaust leaks anywhere near the O2s. Especially upstream of them and within a couple of feet downstream.
I am confident there are no leaks beforehand, I can investigate further- but the PCV and injector issues certainly need addressed. Thanks for all the help