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Hi all, I’m not any kind of technician, but I’m real good with the bolts springs and gaskets bit. my question is, will a bad o2 sensor cause random misfire in this 2003 nissan maxima? I got some code that made it seem the o2 sensor in bank 2 might be the problem. anyone tell me how many o2 sensors this car has? and how hard to replace? thanks much
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A bad O2 sensor could cause a random misfire. If the O2 is misreporting oxygen content, it could be causing the PCM to lean out the fuel mix to a point a cylinder doesn’t get enough fuel to fire. However, sometimes an O2 code means that the O2 sensor is reporting that there’s another problem at hand. Replacing the O2, in this instance, is a case of shooting the messenger. Lets say the engine is already running lean. Changing the O2 might not fix it and then you’re moving on to looking at a bad MAF sensor or a plugged injector or a vacuum leak, etc… and on and on. Don’t throw parts at it is the moral of the story.
You’ve got at least four O2 sensors. How hard they are to replace varies from car to car as well as depends on your resources. It’s been a while, but I’ve done all of them on at least one 3.5 Nissan and two weren’t so bad and the other two were kinda bad. Nissans are cluttered and a little too happy with hold down brackets and tabs for my taste. Then there’s rust. That’s always a wild card with any O2 sensors. Kinda bad can turn downright horrible quick if an O2 is seized in its bung.
How is the car actually running and what, specifically, are the other codes? Can you feel any misfiring and is it constant, erratic, or something in between?
In my experience with many Nissans, the ignition coils start to go bad. You can replace them one at a time, but the next one failing is always close by. I suggest getting a new set of them and doing all at once.
There is no real way that a failing o2 sensor can cause only one cylinder to misfire.
Your car does have 4 o2 sensors. Replacing the bad ones will extend your mileage and the lifespan of the catalytic converters.Eric does have vids on testing bad coils. Basicly, unplug the connector for one coil. Dies it run worse? If yes, then that coil is good. Do this one at a time on all coils until you undo one that causes no major change, that is the bad coil.
See if this helps, P0300 troubleshooting starts on page 302
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