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02 sensors

Posted: Mon Feb 06, 2017 5:16 pm
by sparky1971
i have a 97 pathfinder, 3.3 litre
the codes came up indicating right side 02 sensors faulty, the lower and the one on top. so i changed them and its still miss firing, especially when its all warmed up. should i change the other side as well or could it be that it has a manifold leak, which according to my buddy he had the same issue as me and thats what it was.
thanks and any info is welcomed!

Posted: Mon Feb 06, 2017 9:39 pm
by smj999smj
It's very rare that an oxygen sensor causing a misfire; the rear sensor definitely won't because its only job is to allow the ECM to monitor catalyst efficiency and it doesn't affect drivability. It's possible that it could be caused by an intake manifold leak, especially since both sensor codes were on the same bank. It's impossible to say for sure without doing some more diagnostic work. You could also look for low fuel pressure, dirty or non-operational fuel injectors, to name a couple other possibilities.

Posted: Tue Feb 07, 2017 7:14 pm
by sparky1971
sounds good. i will do some more diagnostic work. the engine itself has lots of power, but as soon as its warmed up, there will be hesitation around 1600 rpm and then it just kicks in power wise like a power band, very adrupt, basically not very smooth.
i will keep checking, thanks!