Which oxygen sensor to replace?

[rubs]

I have 2001 i30 with 143k miles. I already replaced 2 oxygen sensors as mentioned here: http://ww2.justanswer.com/uploads/ba...itb02-027a.pdf and they were Bosch part numbers 13348 and 13374.
I still have check engine light on and mechanic told me that we need to change 1 more that is 3 wire before they can confirm if I need to change catalytic converter since that would be very expensive. Can someone specify which 4 oxygen sensors are for this car so I can order correct part since I already replaced 2.

Thanks
--rubs

[Nahkapohjola]

Originally Posted by rubs

...I still have check engine light on and mechanic told me that we need to change 1 more ...

I guess youre now in the wrong shop.

Why rolling dice with your money when diagnostic can/may tell which one is bad. Its even better to go into stealership and and let em read (just ! read) the code than throwing in parts...

Beyond that, the complicator may be receiving warped signals thus throwing random codes, read = READ your earlier post below. Next answer on that thread what happened, n click/read the CDomain linky.

[The_Scheer]

Better yet than going to the stealership; buy an OBDII reader for $30 ($10 if you have a smartphone and/or laptop and don't need a digi display), plug it in and grab the code yourself. Also, if you haven't gotten the Nissan technician repair manual for the vehicle grab that off the net as well for a whopping $3.99 U.S. and spend a few hours perusing it to get to know your wheels inside out. Is it safe to assume that you are having the intermittent "stuttering" issue at low rpm's as the reason why you are randomly replacing O2 sensors?

[cefirochat]

I have a Nissan Cefiro QR20. Yesterday, the engine stalled whilst I was travelling at 80kmh on the highway. I steered my car to the shoulder - it was still rolling but the engine had stalled. I was using the intelligent key (as usual) kept in my pocket. The manual key was attached to the keypad of the intelligent key. I tried starting the engine but it was completely dead. I read the manual and found that I can't start the engine with the gear lever at position 'D'- 'Drive'
The steering was progressively feeling heavier (because engine had stalled). I shifted the gear lever to neutral, took out the manual key from my pocket and placed it in the key-slot. I turned the ignition switch and the engine started. I managed to get home safely.
Can anyone pls advise the cause of the problem? I have since checked the battery of the intelligent key-it is still good. Neverthe less, past experience tells me that once the engine has started, walking away from the car with the intelligent key in my pocket does not stall the engine. Besides the warning buzzer sounding, there are no other consequences whatsoever. I have done that a number of times - walking away from car back into the house with intelligent key in my pocket. I would appreciate advise from members so that I can get car attended to. My mechanic told me it's the petrol grade but I have not experienced any pinking or jerky engine. Car is just 90000km although it is manufactured in year 2004. Thanks.

[Nahkapohjola]

Originally Posted by cefirochat

I have a Nissan Cefiro QR20. Yesterday, the engine stalled whilst I was travelling at 80kmh on the highway. ...

Engine died like from a switch? Then possibly there is a switch ... meaning possibly ign switch is bad and/or some other point - fuses, connectors etc - in the ign circuit has intermittent cutoffs.

Gas problem would cause stutter and starting problems - which u didnt have?

Find out the specs from your intelligent key, how it is supposed to work. Dealership should be able to answer in this question. (Why would it be possible for it to shut down ign at higway speed?)

[rather_b_boatin]

Back to the O2 sensors, I agree with Nahk & Shceer to read the code being thrown before throwing parts in. I have an 01 w/ 135k and I've replace 3 of the 4 O2 sensors & 1 of the 4 cats. Bad cat was upstream. 2 O2 sensors were both downstream and 1 upstream. If I remember correctly 3 wire is the upstream non-heated, downstream are the 4 wire (more expensive) downstream. Had another experience with a bad MAF causing all kinds of wierd exhaust codes like too rich/lean, cat efficency, O2 sens, ect. Even though bad MAF, MAF never came in during code reading, that SUCKED to figure out. It took this forum and some very experienced mechanics who had seen this kind of garbage before.