Ls400 p0420 code 02 sensor bung question
Hey with the rising price in gas putting in a full tank of premium is really chewing up my wallet and if I could put regular in without throwing a code that would be the ultimate goal
My question is with these o2 bungs, ive only seen people place them on the downstream cats.
Should this just be a case of trial and error if I place bungs on the downstream cats and if I still throw a code id just get the upstream bungs done as well.
With it being regular gas wouldn’t all the 02 sensors throw a code if it sees regular?
Thanks and eli5