03 Xterra Repair (O2 sensor? knocking)

[JeffPowell101]

Hey guys, Thanks in advance for any help here.

I have an 03 Nissan Xterra that is riding very rough. Physically shaking/knocking. I've been told that fixing the O2 sensor will resolve the issue. I was previously told that the catalytic converters were my issue. Here are the codes from my car:

P0302 cylinder 2 misfire detected
P0420 catalyst efficiency below normal (bank 1)
P0430 catalyst efficiency below normal (bank 2)
Po328 knock sensor circuit high input (bank 1)

If it is an O2 sensor issue, will I be able to find directions about how to fix this myself or will I have to take this to the shop?

Can I be sure it is an O2 sensor?

It has not had a tuneup as long as I can remember (6 years) and has just under 180k miles. The problem started about a month ago.

Lately the motor has been clicking, and the car has not been knocking much. I think this is another form of misfire.

[BusyBadger]

Could be an 02 sensor, could also be a bad injector. Swap the #2 injector to another cylinder, clear your codes and see if that misfire code shows up in the new cylinder location. If it does, that's your issue, or at least one of them.

[Desert Rat]

your truck will have 4 02 sensors...one on each exhaust manifold and another one past the first cat....while they may be an issue, the mis fire is what's causing your truck to run badly. Ever replaced plugs, wires, cap and rotor? If not, it's way past time and you might just get lucky.

Ive used this method to diagnose what cylinder an issue was on...Pulling one plug wire at a time to see which one doesn't make it run worse than it's already running.

[memaso]

Start with new plugs, wires, distributor cap and rotor, PcV. Clean your throttle body and plenum, EGR, check your air hoses.