Engine Mechanical problem
1997 Nissan Altima 4 cyl Automatic 91000 miles
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I am not sure what to do. The knock sensor code has come up a few times after clearing it. I have recently, within the last yr, replaced the OXY sensor and MAF. The car seems to drive fine, but i don't want to take the chance and have the engine blow/burn out, whatever can happen. When i turn the car on the engine seems to rattle but calms as i continue to drive, but it has done this for a while. The knock sensor has only come up last 2 months. It will cost me 300 to replace it and i can afford it, but do i need to do it? I have been hit fixing a lot on this car within the last yr, but i want it to last a few more yrs if possible. I only have 90k miles on it. Any advice would be great. Thank you for taking the time to look and comment.

whats the code, can you post the P**** code here that way i can try and see if its an issue with the sensor or other means/

is that the only code showing up?

the code was P0325( i think it said knock sensor malfunction if i recall correctly). It pops up 2 times in it. I have a friend who is a mechanic and does the basic stuff and he has a tester that you plug in to the computer and had cleared it a few times but it pops back up. I have read that you can keep driving with it and it could be ok. I also read guys driving with it for yrs with no problems and others saying i should have it fixed before it destroys the engine. I don't know what to do.

yes you are correct.

the causes would be a bad knock sensor or damaged wiring!

Check the resistance of the knock sensor first of all before replacing and compare it wiht the specifications for the sensor.

next Check for broken, cut, frayed damaged wires leading to the sensor also check for corrosion on the connections

Replace the knock sensor if all above is good

How do i check the reisistance? To check the wires, etc do i use a flashlight and see if i see anything? Do i bring it to a shop and have them check it?
The knock is almost impossible to get to. I don't have a lift and just jacking it up and looking seems like i won't be able to do it on my own. I know where it is from pictures but i can't get to it.

use a ohm meter and touch on each of the sensors signal and ground wire.

to check wires best way is to remove the wiring harnes and check the voltage drop and resistance of um, a flashlight will show obvious cuts and wears, but they could be bad on the inside.

if you take it in they can do a pin to pin test on it easier then you can, id check the sensor for now, if its within specs id take it in.