I am looking to replace my front O2 sensor(s) on my 2004 1500 3.7L v6.

I traced the exhaust from the manifold and I see on the driver side a bulge in the pipe (cat converter?) and an O2 sensor right AFTER it which would make this the back O2 sensor?

On the passenger side, I see an O2 sensor right BEFORE the bulge in the pipe (another cat converter?) which would make this the front O2 sensor?

Is this correct? Is the bulge in each side a cat conv or am I misinterpreting?

 

Yes, the bulges are the converters. One per side. You want to replace the sensors between the engine and the converters.

 

1/1 O2 is front drivers O2
1/2 O2 is rear drivers O2
2/1 O2 is front pass O2
2/2 O2 is rear pass O2

 

Thanks fellas! I will hit the dealer tomorrow to get the part since some have issues with non OEM sensors from other threads I have read.

Your help is much appreciated!

 

be sure to report back how it works out for you.

 

I replaced the passenger side O2 sensor and now I have a hard time noticing the shudder when stopping at all!


I did however notice I do indeed have 4 sensors in all. So I got the driver side upstream sensor on order. May as well get them both done as they are way over life expectancy already.

I guess that even if they haven't "failed" yet, they can still degrade?

 

Yep, seen many an O2 cause performance loss (and an EGR and PCV as well) and not yet be bad enough to pop a CEL...

 

what O2 did you replace it with? price?

 

I used the dealer part 56028994AA at $70.10.

 

thanks