Is this a legit upstream Oxygen sensor?

[RABID_MP5]

Found on eBay for 25 bucks. OEM plug on it.

https://www.ebay.com (commissions earned)

Same as the SMP Rock has for $140

http://www.rockauto.com/catalog/x,carcode,1387447,parttype,5132

Not sure what's going on here? It's a deal if really the right new upstream sensor.

 

[i12drivemyMP5]

Looks like it to me and the FSN part number yielded this in google search.........says 2002-2003 Protege5

http://www.jimellismazdaparts.com/products/Mazda/Protege/SENSOR--OXYGEN-O2/1946489/FS7N18861-9U.html

Better jump on it before I do, lol..............says they has 10 available

 

[kcbhiw]

I had two of those inexpensive Ebay O2 Sensors fail in a year. I ended up biting the bullet and going with a Bosch and haven't had any problem's since. Buyer beware.

 

[i12drivemyMP5]

Were they factory FSN part number oem part like these or something else?

 

[CheeseHelmet]

Found on eBay for 25 bucks. OEM plug on it.

https://www.ebay.com (commissions earned)

Same as the SMP Rock has for $140

http://www.rockauto.com/catalog/x,carcode,1387447,parttype,5132

Not sure what's going on here? It's a deal if really the right new upstream sensor.

Call them and make sure it's legit, it's not so hard for a bad manufacturer (or ebay seller) to use the same part numbers for their crappy parts. The OEM upstream sensor is made by Denso (at least that's what was stamped on mine), you can find exact replacements on rockauto for ~$80. I used the Bosch 13887 sensor and didn't haven't had any problems.

I agree with kcbhiw about cheap O2 sensors, you get what you pay for. I bought the cheapest ($70!) universal O2 sensor from NAPA when I first got my P5 to replace the downstream sensor and it lasted less than a year. They replaced it for free and the replacement died a little over half a year later. Since then I've replaced it with a Denso-brand sensor and have been living CEL-free ever since.

 

[RABID_MP5]

Hmm this complicates things a bit. Notice I never really verified that I actually NEED an O2 sensor; I'm having a hesitation issue and figured for 25 bucks it was worth a shot. Then again, if the sensor IS the problem, even a cheapo one might fix the problem for awhile, which would at least verify that's the problem. I could upgrade when it dies. My sensor is name brand has maybe 50K miles on it.

My issue is always identical. You come off the throttle awhile and when you press down again there's like a .1 second pause where it's like a cylinder or two completely missed firing, typically at 1200 RPM or so - then it takes off fine. I had tried coils to no luck. Def seems fuel related. It's done it for a year now, very slowly getting worse. No CEL or stored codes.