I think you are confused about your air intake, MAF and intake plenum being crossed overwell.. the mixture control is governed in part by the O2 sensor..it adjusts rich and lean settings and on my twelve the left O2 unit tells the right bank what mixture to set and the rightO2 unit tells the left..
Hmm, in previous posts you write;As I said in my 12 the left tells the right and the right tells the left.. I think it must be the same for your 8..however .. you will now have hit the extreme mixture setting on one side only way to sort it is pull the codes and list them here..then we have info..not speculation..
The right hand O2 will adjust the mixture on the right hand combustion (bank),the left O2 unit tells the right bank what mixture to set and the rightO2 unit tells the left..
Ok, I think we have to get things strait here. This fault is for a car with M119, single MAF,looks like your fuel system has hit the buffers on one side like i said previous..L controls R and R controls L take lead out of maff and unplug the o2 sensors.. then fire up and listen see if it smooths out..