Hoping yall can keep my down a logical path here. I've been muckin' around a decent amount so hoping I can get grounded on a solution path before I get ahead of my skis
Background - Bought '04 LX w/ 195k miles in 2020. Changed all 4 O2 sensors @ about 200k in sep 2022. during this install, i remember the upstream passenger side cat didnt go in smoothly (felt like i was crossing threads). i recall soon after getting the cat codes where i think all this started. in feb 23' i got a new sensor for the upstream pass cat in case i botched the install. took my time with it and chased the threads and all that good stuff. since then codes have been intermittent. they would come and go. since they were coming and going i always attributed the issue to low rpm city driving which is definitely a culprit but i dont know anymore. i would go for several hundred miles with no CEL lights, then out of no where they were back again. P0430 / P0420 was typical
Exhaust Work
last year is when i started muckin around. I put in the Doug Thorley shorty headers with new OEM manifold gaskets. I routed the passenger sensor up around the engine bay away from direct heat sources as directed on DT install threads on MUD. I chopped the oem muffler/resonator and put in a flowmaster muffler. At this point I installed new OEM gaskets for header/cat & cat/tail pipe interfaces. I had an exhaust shop do the muffler install and at this point i asked him to verify no exhaust leak. He confirmed there was no leak but i saw him go to diagnose and check and it was quick. I didnt feel like he looked very hard but what do i know. I also do not hear any audible clicks.
1. Since this time so about 1.5 year and lets say 2.5 - 5k miles codes stayed intermittent. they would come and go and i would always get 2 codes bank 0430/0420. If memory serves it was always P0430 and P0420 just like before the exhaust work.
2. A few weeks ago I was reading about smoothing out potential upstream issues. I cleaned the MAF sensor and disconnected the battery and this got rid of all codes for a few hundred miles / couple months.
3. a few weeks later ive been meaning to get around to it and replaced the fuel filter
Well today CEL is back and I am looking at P0430 only. My thought is the MAF cleaning really worked because now I am only looking at 1 code instead of two. My gut is telling me its the upstream passenger O2 sensor. I am just thinking of this now, but I did use my old 02 sensors for the DT headers and as I understand those crush washer dont like to be recrushed.
Am I missing anything obvious? Are you guys also thinking the sensor is the culprit? Anything additional upstream i should look at?
Can lastly confirm no collant or oil leaks so far as i know...
Background - Bought '04 LX w/ 195k miles in 2020. Changed all 4 O2 sensors @ about 200k in sep 2022. during this install, i remember the upstream passenger side cat didnt go in smoothly (felt like i was crossing threads). i recall soon after getting the cat codes where i think all this started. in feb 23' i got a new sensor for the upstream pass cat in case i botched the install. took my time with it and chased the threads and all that good stuff. since then codes have been intermittent. they would come and go. since they were coming and going i always attributed the issue to low rpm city driving which is definitely a culprit but i dont know anymore. i would go for several hundred miles with no CEL lights, then out of no where they were back again. P0430 / P0420 was typical
Exhaust Work
last year is when i started muckin around. I put in the Doug Thorley shorty headers with new OEM manifold gaskets. I routed the passenger sensor up around the engine bay away from direct heat sources as directed on DT install threads on MUD. I chopped the oem muffler/resonator and put in a flowmaster muffler. At this point I installed new OEM gaskets for header/cat & cat/tail pipe interfaces. I had an exhaust shop do the muffler install and at this point i asked him to verify no exhaust leak. He confirmed there was no leak but i saw him go to diagnose and check and it was quick. I didnt feel like he looked very hard but what do i know. I also do not hear any audible clicks.
1. Since this time so about 1.5 year and lets say 2.5 - 5k miles codes stayed intermittent. they would come and go and i would always get 2 codes bank 0430/0420. If memory serves it was always P0430 and P0420 just like before the exhaust work.
2. A few weeks ago I was reading about smoothing out potential upstream issues. I cleaned the MAF sensor and disconnected the battery and this got rid of all codes for a few hundred miles / couple months.
3. a few weeks later ive been meaning to get around to it and replaced the fuel filter
Well today CEL is back and I am looking at P0430 only. My thought is the MAF cleaning really worked because now I am only looking at 1 code instead of two. My gut is telling me its the upstream passenger O2 sensor. I am just thinking of this now, but I did use my old 02 sensors for the DT headers and as I understand those crush washer dont like to be recrushed.
Am I missing anything obvious? Are you guys also thinking the sensor is the culprit? Anything additional upstream i should look at?
Can lastly confirm no collant or oil leaks so far as i know...
