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O2 sensor with Flowmaster catback

2K views 10 replies 6 participants last post by  cliffyk 
#1 ·
My 02 GT has a code for oxygen sensor bank two. Should I replace both sensors or can they be cleaned? Is there a particular sensor to use or not use with the Flowmaster pipes? Thanks.
 
#2 ·
Did you go catless? If not then you shouldn't be throwing codes because of the exhaust... I would change the sensors and do a little more investigation as to why the codes were thrown in the first place... You should be able to just use standard sensors with the new pipes.
 
#4 ·
It may just be time for new ones to be honest. After around 80k+ miles it wouldn't be a bad idea to replace them. Mine went bad a few weeks ago and I was throwing a code similar to that and was running rich enough to get about 9 mpg in town. It was awful.

---------- Post added at 09:39 PM ---------- Previous post was at 09:36 PM ----------

It may just be time for new ones to be honest. After around 80k+ miles it wouldn't be a bad idea to replace them. Mine went bad a few weeks ago and I was throwing a code similar to that and was running rich enough to get about 9 mpg in town. It was awful.
And I would change the pre-cat sensors first. If I understand correctly, those are the ones that give the proper air/fuel ratio and will have the biggest effect. The post cat sensors I know are for emissions purposes but may do more. Someone else a little more educated on the subject may can follow up further.
 
#11 ·
As is usual the Advance Auto rep doesn't know "it" from Shinola. There are two cylinder banks, 1 and 2, 1 being that on the passenger side. Each bank has two O² sensors one upstream of the cats (#1) and one downstream of the cats (#2):



The sensors are referred to as shown in the diagram, HO2S-12 for instance is Heated Sensor - bank 1 sensor 2.

Before you start buying O² sensors you need to find out what the code(s) were as most of the DTCs mentioning "O² sensor" in the generic description (which is what the FLAPS people work from) indicate a good sensor reporting some other problem. When you get the codes look them up here to see what the shop manual say about them, including possible causes and diagnostic tips...
 
#8 ·
Rear sensors don't do anything except tell you if you're cats are working on not. If they are bad you'll be okay without replacing them. But if it was me I would replace so that your cel isn't on all the time. That way if something really happens you'll be able to tell when the cel goes on
 
#10 ·
And the rear ones are real easy to replace.

If you replace it and it still throughs a code I have a trick on how to fix without buying the mil eliminators, but the o2 sensor has to be good not bad.

---------- Post added at 10:15 AM ---------- Previous post was at 10:14 AM ----------

The trick works on o/r x or h pipes with out cats.
 
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