P0420

@Torspd @Lucario Runner

 

I had this same code after an engine swap. It turned out to be the donut gaskets connecting the Y pipe to the manifold. I barely noticed a black stain on the flange. New donut gaskets from the dealer and I was good to go after I installed them.

 

Because Commi-fornia. Ultra high emissions rating.

 

So hypothetically speaking, one non CA resident could delete the two converters forward of the O2 sensors and suffer no ill effects?

 

No, the O2 sensors will detect what is upstream. If you delete the forward cats the O2s will throw error codes. Anything behind the O2 sensors the truck will not know about, but isn't strictly legal. Some states may check with inspections, others don't.

 

Thats what I meant to say. We don't have an inspection law where I am and there will still be two cats on the truck.

I don't plan to delete them unless they become a problem down the road, anyway.

 

O2 sim for the fronts.

With the advancement in sensors and systems, the old anti foulers barely work these days, unless lady luck is on your side.

Works great on my old Bimmer though.