Which 02 sensor to put spacers on?

[joseph_2880]

So I put on a header and now i get a constent p0421 Check engine light. I was told to put the Spark Plug foulers inbetween the 02 sensors and the exhaust but I dont know which 02 sensors need thease gappers on them. I have 3 02 sensors altoghether. One on the Manifold/Converter, one before the second cat and one after the second cat. Do I need to put the spacers on all three 02 sensors or what?!?!

[joseph_2880]

I just wanted to add to this post that i have done research prior to this post and found the details of drilling the 1/2 inch hole and everything. But the only indication of, how many or where, was one members post about putting the spacers on all three 02 sensors.
I want to be correct on how to install these spacers before i just go off and put them on every sensor.

[Redhaze]

V6? And also did you reset ecu after the swap

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[joseph_2880]

okay so I found out I only have 2 o2 sensors and not 3 like i stated before. The engine is a 2.4L V-6 and I did unhook the battery for about 15 minutes, if that is what you mean by "reset ecu after the swap."

[oakrdrs187]

Its not a V6 nor is it a V4 if that was your next choice. It's a 2.4L I4, the cylinders are in-line.

You have 2 O2 sensors and the only one that needs spacing would be the 2nd one, don't touch the first O2 as it's not the one that determines how the pre-cat performs.