If the exhaust is partially clogged, wouldn't the engine temp increase?
The exhaust in this car is a little different than I’m used to. There is a upstream o2 in each manifold then a cat then the downstream o2 then a single cat where the pipes merge. Usually the o2 that measures efficiency is after the secondary cat. Not before it. I did get back pressure readings of 25psi at both the upstream and downstream o2 sensors. That eliminates the primary cats and leaves the secondary one and the muffler