P0431 Question

[Anker]

The other possibility is that your primary catalytic converter has gone bad. I have seen that code a couple of times when I have driven long trips at a leisurely pace. First time I replaced the O2 sensors on that side. The next time I knew it wasn't the sensors, so I did two things. I stopped driving long stretches at a leisurely pace and the code reset, and I bought a manifold with a catalytic converter to replace the bad one. The code hasn't come up again this year, so the replacement manifold is still sitting on the shelf. I'll do the replacement at an appropriate time or when the code reappears and doesn't clear when I up the pace.