99 Explorer Sport 2WD 4.0 pushrod

[Curmudgeon]

So... get a "check engine" light. Run it down to my buddy at the shop, Bank 1, sensor 2. Bought one. Read up on it (including remove seats, carpet, console and trans tunnel) then got under vehicle...and I can see it, touch it, even remove it..except...I need to make sure.
I tried a search on these forums at the top..in a new window...in fact it is still open, says "loading" and goes nowhere.
There is passenger side front cat, "Y" from left side and cat, one more cat, then muffler. Top rear of this second cat is what I believe to be the one, but all I have read says 4 of them.
I found maybe three.
Are the plugs different, so if I find the right one it is confirmed by plug mating?
I'm gonna do this on my back, and any more that's rough for me, so thought it best to check here first.
Thanks.
Dave

 

[vroomzoomboom]

sensor 2, or downstream is the one after the first cat. bank 1 means its the one on the side of #1 cylinder (for any v6 or v8 ford, normally the passengers side). SOHC and 5L have 4 o2 sensors, but i cant remember if the ohv ones do or not. i think there is only three of them.

 

[Curmudgeon]

Okay..thanks.
Basically, even if it's Bank 1, it's the only one at the back, after the Y pipes come together.
Dave

 

[fast_dave]

In my experience with this engine, replace all three of them.

The MPG and Performance increase will more than pay for them.

Make sure to re-set the computer after they're replaced.

Buy from ROCK AUTO - (btw; they're BOSCH from the factory)

YMMV -

 

[Robman]

I was pretty confused as to why you removed the seats/console etc for 02 sensor replacement..

 

[Macgiobuin]

1999 early production had 4 oxygen sensors: B1S1 B1S2 B2S1 B2S2, late production had 3 sensors: B1S1 B1S2 B2S1. B1S2 actually reads the exhaust from both banks. If you have no wires in the PCM for pins 61 (violet/light green) and 96 (tan/yellow), then you have the later production version.