what are the symptoms of a bad upstream o2 sensor?

Hi I have 2007 RX-8 and the oxigen purge control valve upstream just went bad please give me a quote for a new one cause autozone is charging me 217 for it thanks

Does anyone know how many oxygen sensors a 2004 RX8 auto has?

There are two, although the upstream one is now referred to as an 'air fuel ratio' sensor.

You have UPSTREAM and DOWNSTREAM. If you have en engine light on make sure you get the code number to make your diagnosis as accurate as possible.

Paul.

Yo, I went to my friendly Advanced Auto store to hook up to see what my CEL is on for. The dude didn't give me any code numbers but he said it was BANK 1, SENSOR 2. He said that meant it was the upstream sensor. True? Was he correct?

Incorrect.

Bank 1 sensor 1 is upstream, it is the critical one that controls AFRs and fuel trims. It is the more expensive sensor and harder to reach and harder to replace.

Bank 1 sensor 2 is downstream, it is the one in the cat that monitors cat efficiency and can be ignored unless you need OBD2 emissions testing. It is around $100 cheaper than the upstream, and can be replaced relatively easily.

Awesome! A 2 minute wait for a totally informative reply! Thank you!!

And yep, I believe it, cuz there is absolutely zero change in performance. I do want to replace it though, just so I can clear the CEL so it can alert me to a possible real problem that might happen one day.

Thanks again! Easy, huh? In the CAT? ok...

Just a side note - even though this is almost the oldest production RX-8 known to man, LOL, it only has about 20.5k miles on it, was 100% garage-kept, under blanket, and drank only quality premium gas throughout its entire life. I dunno,,, why would an O2 sensor fail?

Something could have chewed through the wiring, the wiring could have degraded by time enough that it can't send a good signal, dust collected in the head altering the performance signature, etc...

No part lasts forever. Pretty much every component out there can fail on time alone with zero miles on it.

Yeah... I'll report back with anything found mechanically. I wouldn't know how to check it electrically, i have a multimeter, that's about it.

So, I assume it's easily accessible from underneath, right?

And, thanks again!

I have a 2005 RX8. Can I get a price check with shipping to zip 41042


I am looking for front and rear oxygen sensor. CEL Code P0037 popped up and I might as well replace both to get it out of the way incase the front decides to die.

Well, procrastination isn't always a bad thing - my CEL went out!

I have an Infiniti G20T that did this for a long time. It's my daily driver. Now, the CEL stays on all the time, but for a long time, it went off for a few drives, then back on for a while, and so on. But I just ignore it, knowing it's the O2 sensor, and just keep an eye and ear on the engine vitals.

This RX-8 is more special though. If it comes back on, I'll get back on the task of replacing it.

Well, shoot! The CEL came back on.

OK, what is the preferred downstream O2 sensor make & model?

MazMart, please send me a quote... shipped to 29078

(2004, MT)

LINK to our Website
 

This will be the easiest way to buy the sensor from us:

https://www.partswebsite.com/mazmart...i=2&type=parts

I hope I can serve you while saving you money.

Paul.

ok, so,
upstream is front
downstream is rear
right?

Yes sir, correct.

Paul.

Need one too
 

Hi Paul.
I'll need to order a rear O2 sensor (downstream) for my 04 Manual tran RX8 if I could get a price quote. Shipped to 83434. Thank You.

Hi Braden,

I'll send you a quote. I intend to put them on my new site tomorrow.

Paul.

MAZMART - Serving The Mazda Community Since 1980. RX8 Oxygen Sensors

This is the OEM but at discount.

Paul.

I need an upstream O2 sensor for a 2004 Mazda RX8 with auto. transmission.

Here is the new link for purchasing our reduced cost oxygen sensors:

MAZMART - Serving The Mazda Community Since 1980. RX8 Oxygen Sensors

Paul.