B4U Task Force Admin
The engine computer users the oxygen sensor to decide how much fuel to squirt not just for omptimum running but also to add extra fuel so the catalytic converter will run hot. This takes extra fuel. some have a 2nd oxygen sensor to see if any extra oxygen is going thru the catalytic. if anything seems wrong it will go into limp/quess mode and squirt extra fuel just to be sure it will run but it will be a guess and will usually give poor mileage or even poor running. American manufacturers need to rethink the whole engine control system to get better mileage not just reduce emissions.
You beat me to it... 🤣You need to rethink posting in a dead thread, did you bother to read the post right before yours?