Downstream O2 sensor operation - P0420

[cabmandone]

Originally Posted by Bob Kontak

In post one I said I have a scanner that says it is swinging wildly.

This is in conjunction with identifying the rear O2 sensor was kaput and post replacement indicted bit swings in rear O2 sensor swings.

It is a Snap-On MT 2500.

Sorry! Missed that, been a long day. I have been fighting a P0420 in my Taurus X. Downstream on bank 1 was fluctuating terribly. From what I read I came up with changing the upstream since it determines the fuel mixture and the downstream is just reading what the Cat is doing. I had the same P0420 a few years ago and changed upstream which cleared up the problem until recently. Now I just look at the CEL and every once in a while get out to check my engine just to make sure it's still there

BTW, my bank 2 downstream fluctuates but not as much as the bank 1 downstream. I have never seen my downstream on either bank hold a steady reading. I'm not talking big fluctuations but it does change

[mattdavis11]

Raise it up!

[Bob Kontak]

Originally Posted by mattdavis11

Raise it up!

Expand on that.

[Bob Kontak]

Originally Posted by cabmando

Now I just look at the CEL and every once in a while get out to check my engine just to make sure it's still there

You are so in one of those EPA non ozone nonattainment areas.

You are safe and you deliver footballs to the world. Your CEL is but a nuisance.

Thank you.

[Jesset100]

Get this
O2 OXYGEN SENSOR EXTENDER EXTENSION SPACER M18 x1.5 BUNG HHO ADAPTER OBD2 02

[Bob Kontak]

Originally Posted by Jesset100

Get this
O2 OXYGEN SENSOR EXTENDER EXTENSION SPACER M18 x1.5 BUNG HHO ADAPTER OBD2 02

I will neither confirm nor deny that I will take this approach.

$7