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o2 sensor question

26 July 2005
Fort Myers, Florida
Just installed headers ('96 NSX-T) and check engine light keeps coming on. Checked it with a diagnostic tool and the code is a "manufacture mixture problem". If I had the two cat o2 sensors reversed, could that be the problem? The o2 sensors on the headers are new OEM with the same part number. I had no problems before the header installation. Now,the car acts loaded up until 4,000 rpm, the clears out and runs great. Any advice?
How did you get them out - did you use any penetrating fluid? (WD40, PBBlaster etc)
If any got on the sensor they are screwed.
Unplug one, then check your error codes - that will tell you at least if you have them plugged into correct respective harness.
As I stated in my post, the sensors (upstream) were brand new - both had same part number. Nothing was used to remove or install them. The downsteam sensors in the cats were never removed. I plan on re-connecting the cat sensors if I got the connections reversed if it makes a difference.
First thing to do is swap the cables or trace them, since now we know you did not get WD40 all over them:). I assume you have a generic OBDII scanner? The code is not Acura specific. Do you have a code number?

No more check engine light after about 20 minutes of driving. I found that there is no way you can get the cat o2 sensors mixed up - they only plug in one way. Car runs fine after about 4,000 rpm - before that it feels "loaded-up". Not horrible, but was much better before I installed the headers and new upstream o2 sensors. Does anyone know if the two o2 sensors upstream are exactly the same? They both had the same part number. If not, my next step is reverse them when the car cools down. If the check engine light comes on again, I'll check codes with factory manual. Thanks Larry.
Thanks, that's kinda what I thought. Any idea why the car seems to slightly load up and stumble a bit under 4,000rpms, then runs fine? Never happened before header installation. Will driving it more solve this? Does the ECU have to "relearn" the new o2 sensors...It's a '96. It's making me crazy.