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I can’t figure out why my o2 sensors keep failing and i can’t seem to find anything on this topic. i don’t want to keep wasting money on new o2 sensors so i won’t be replacing it until i figure out why it keeps happening. could anyone help me out with this?
 

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I can’t figure out why my o2 sensors keep failing and i can’t seem to find anything on this topic. i don’t want to keep wasting money on new o2 sensors so i won’t be replacing it until i figure out why it keeps happening. could anyone help me out with this?
Are you using Ford"s 02 sensors, or after market parts,are all your connections clean and in good condition?
 

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Bosch use to be good but became a POS....won't purchase anything from them for the past 10+ years. Stick with OEM
 

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2014 GT, 1967 Fairlane GTA
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I can’t figure out why my o2 sensors keep failing and i can’t seem to find anything on this topic. i don’t want to keep wasting money on new o2 sensors so i won’t be replacing it until i figure out why it keeps happening. could anyone help me out with this?
How exactly do you know that your O2 sensors keep failing?
If they are there's probably a short in the wiring/connector somewhere. Like mentioned cheap aftermarket sensors also aren't reliable.
Bosch use to be good but became a POS....won't purchase anything from them for the past 10+ years. Stick with OEM
I just bought a Bosch O2 sensor for my Ford 2.0 Duratec in my daily. Bosch makes the O2 sensors for many OEMs including the one that I just bought. I checked thoroughly and the Ford boxed one and the Bosch one that I got were identical right down to the very slightest details thanks to Rockauto for having multiple pics that you can zoom in on. I went with the one in the less expensive Bosch box instead of the one in the Ford box.
Usually, I do only buy Ford parts but in this case the Ford part actually was the Bosch part so I saved about $25. Agreed that many companies are shells of their former selves though. Budget engineering in this current disposable society has unfortunate consequences.
 

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I've used NGK on my 4.6 (when it was in) and no issues over a three year period. Still good now, both sets!

You need to check the engine "tightness" as far as intake, exhasut, etc. to be sure all is in good working order. These, along with other items, can cause pre-mature failure.
 

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Since you are getting heater circuit codes for both O2's, check your wire harnesses for worn spots between the O2 and as far forward as you can. I believe they will trace back to a branch point where they split and run down left and right. The heater circuit "pre-heats" the sensor so that the sensor begins to function instead of waiting on the exhaust temperate to reach 600 degrees to activate it.

Here's a really good in depth video on how O2 sensors function.
 

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2014 GT, 1967 Fairlane GTA
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i’ve been getting heater circuit codes for both downstreams. not sure what that is either? i’ve been buying them from oreilys do i suppose they’re aftermarket
It would be helpful for you if you just posted the exact codes that you're getting here.
Some O2 sensor codes are purely electrical in nature and some can mean that the O2 sensor itself can be defective. Others will tell you that the up/downstream readings are too similar while some are warnings that there's an air/fuel mixture issue. It all depends on the code itself. If it's a recurring O2 heater related code then a wiring issue can be the cause but in rare cases a bad PCM can also be the cause.
Oreilly's won't be selling you Motorcraft sensors so anything else will be aftermarket. Bosch and NTK are actually the main suppliers for Ford and the other car makers. However, the chance that every O2 sensor that you've bought has been defective is pretty slim so something else like an open, short, or ground in the circuit somewhere is likely.
 
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