Does any body know where the upstream o2 sensor is???

 

Help me out guys

 

Just had my CEL come on today with the 0303 code too. I believe it is down on the muffler but the electrical connector is in your engine. Would suggest buying a haynes to show exactly where it is and how to change.

 

Upstream O2 sensors are off the front (left) and rear (right) banks of the engine UPSTREAM of the main catalytic converter.

if you look at the underside of the car or in a tune-up guide, you will see, the y-pipe coming off the front and rear into the exhaust.

the front O2 sensor is just around the stock heat shield and plugs into the harness in front of the NISSAN spark plug cover in your engine bay.

the rear or right side upstream O2 sensor is hard to see unless you are under the center of the car but is in the similar position on the pipe leading straingt into the bank bank of the manifold.

FYI, the downstream O2 sensor is on or just past the actual Catalytic converter prior to the long resonator before the rear suspension.


Just imagine this having another piece pointing up the same height as the middle pipe on the far left part of the picture and the O2 sensors bolt in there about halfway down each up-pipe.

Two upstreams normally for 4th gens...more possible for 5th IIRC adn downstream is to the right past the CAT on the picture.

 

I Got the Code 0509, Like 3 people told me its my Upstream o2 Sensor from the forums before, they told me they got the info from the Haynes Manual, This is the reason I have a rouph idle right??? I also need new spark plugs and soooon, my car is Misfiring So BAD, it sounds like a V8 on crack or something cause I have a home made intake, like all my pulling ablitiys are gone, I have no more power left in her, untill I get new sparks!!! Any one know where to get cheap ones from around Chicago, Pepboys said they only have NGK Platiniums for my car, but they are like 15 a pop,

 

Any body?

 

HELP ME PLEASE

 

you could have bought a new oxygen sensor from Jerry Rome Nissan and the regular NGK coppers and had them installed and running fine and dandy in the time you are waiting for more info on this.

 

The Stealership, How much would this all cost? Estimation will be nice

 

Just contact Ken Athas at Jerry Rome Nissan www.jerryromenissan.com and talk to him about a quote for Maxima.ORG parts

he definetly has taken care of me and beat many other dealerships between 25%-50% in price shipped to me.

 

Thanx much