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Discussion Starter · #1 ·
My gt has the factory o2 sensors at 185000 miles. Car runs great. Gas mileage is a few less than when it was new. I bought it off the showroom floor it's a 2000. Should I replace the sensors if so just the fronts or all? No codes at all also. Thanks
 

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Yes, the improvement in fuel economy will more than cover the cost of the sensors (the degradation sneaks up on you)...
 

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Can I just change the fronts ones or do I need to do all 4
Just the front, the rear sensors do nothing except monitor the catalytic converter efficiency--they have no effect on engine control...
 

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Found replacement at rockauto. Denso for 25.79 will that work you think?
They will all--Motorcraft, Denso, Bosch, etc.--work, do not fear the urban legend that "only OEM Motorcraft will do the job". Bosch invented narrowband (and wideband) O² sensors, so they sure as crap should know how to make them--Denso just ripped off their design.

Every non-Motorcraft O² sensor "failure" I have repaired has been the result of poor installation (damaged/contaminated) or that the O² sensor was not defective. Far too many oxygen sensors are replaced because the DTC description just happened to mention "O² sensor", but the issue was a good sensor reporting some other problem...
 

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Discussion Starter · #7 ·
So changing the upstream o2 sensors might get back some mpg? I never knew that I should change them at a certain interval. I guess now is better then never.
 

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So changing the upstream o2 sensors might get back some mpg? I never knew that I should change them at a certain interval. I guess now is better then never.
I guaranty that at 185k they are sluggish and have low output voltage. This tell the PCM the mix is lean (when it really isn't) and the PCM adds fuel, making the mix too rich. If you were to observe the Short Term Fuel Trims you would find they are in the +10 to +15% or better range.

It is not until the STFTs get to more than +25% that a DTC is thrown...
 

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O2 Sensor question

I guaranty that at 185k they are sluggish and have low output voltage. This tell the PCM the mix is lean (when it really isn't) and the PCM adds fuel, making the mix too rich. If you were to observe the Short Term Fuel Trims you would find they are in the +10 to +15% or better range.

It is not until the STFTs get to more than +25% that a DTC is thrown...
Hi, good info. i was not aware of that myself. Will change my set also.
 

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Will I need to use anti seize compound on the threads?
You can, most come with anti-seize on the threads and a plastic cap to protect the sensor:



This is a new Bosch 17014 LSU4 wideband sensor that happened to be in the cabinet right next to me. It is a readily available (all FLAPS stock it) direct replacement for the Bosch sensor included with most wideband systems:
 

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I got a 98 mustang gt and I'm on rockauto as well and that got 4 wires for 40.79 one up and 3 down but on my mustang I got two up and two down does it really matter if it says 1 up and 2 down can't I just get it and put two up and two down?
 

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My 03 just cracked 100K. I am going to look into it as well. I heard that they should be changed around every 75k as recommended by Ford. Is the wide-band better?
 

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My 03 just cracked 100K. I am going to look into it as well. I heard that they should be changed around every 75k as recommended by Ford. Is the wide-band better?
Wideband sensors are entirely different beasts, intended for monitoring AFR when tuning, and for service use in some newer cars that are configured to use WB O² sensors--our cars are not and they would not work...
 

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I got a 98 mustang gt and I'm on rockauto as well and that got 4 wires for 40.79 one up and 3 down but on my mustang I got two up and two down does it really matter if it says 1 up and 2 down can't I just get it and put two up and two down?
You car has four O² sensors, two "upstream" (one left and one right before the catalytic converters) and two "downstream" (also left and right, after the converters)--they are all 4-wire units...
 

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Discussion Starter · #17 ·
I bought my o2 sensors from another place for 27 each and they are the same part number as sold on am for 46 the Ntk ones.
 

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Why not just buy some mil eliminates for 20 bucks that plug into factory wiring and forget about it then u could remove the cats without throwing a code and not have to buy 100 dollar o2 sensors for these hippies around here
 

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Why not just buy some mil eliminates for 20 bucks that plug into factory wiring and forget about it then u could remove the cats without throwing a code and not have to buy 100 dollar o2 sensors for these hippies around here
Do they mil eliminates have any benefits aside from replacing the O2 sensors? Easy to re-install the O2 sensors for inspection purposes?
 
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