P0135 O2 Sensor Bank 1 Sensor1

[mysterious_rahul]

Hello Fellas,First Of All Wish You All A Mery Christmas.

I have a 2000 Nissan Maxima, with California Emission with Milage around 112k. It has the Service Engine Soon Light on since last couple of months but some 10 days back it has started behaving weird. Whenever the car engine is cold (in the morning or in the evening) it kind of misfires, so badly that I can feel the vibrations.

I went to Autozone and the read the OBDII Error code as : P0135 O2 Sensor Bank 1 Sensor1.

Now,I am an absolute begineer and I am not very sure where can I find the Sensor Bank 1 Sensor1 in the car.

Very basic question: Is it under the hood or under the car floor? I mean do I need to go under the car to fix it or can I do it by opening the hood.

I hope you are getting what I am trying to see. I have seen a few diagrams which tells about the location of all the sensors but I am not sure if its under the car or under the hood. If its under the hood I will try by myself otherwise I will have to see some car mechanic.

My Observation: The RPM of the car in Idle state is just about 1k rpm and when I put it on drive and keep it at halt then it drops to almost 750 rpm. Is it something to do with the Spark Plugs / Ignition Coils?

Pls Pls Help Me out of this.

Thanks in Advance.

[ehdash]

(B1) is the right hand side of the engine bay (Back side by firewall) and S1 is the front O2 sensor, you'll have to do service it from underneath vehicle. Note: around 750-800 RPM at idle is normal under load. There is also a Technical Service Bulletin on replacement of the O2 sensors and reprogramming the ECM.