P0420 2006 Nissan Maxima -

Question

how to fix a po420 code ? it also had a po302 misfire code also. Should i give it a tune up

Answer 1

Yes you should start by replacing the spark plugs, and use 91 octane fuel from Shell or Chevron if you dont already use it and reset the codes

If your car still have the P0302 misfire on cylinder #2 swap the ignition coil with another cylinder and see if the code move to the other cylinder if no your ignition coil is bad. You can swap #2 and #4