My P1273 journey summary.

I had traded a motorcycle for my 2004 G35 coupe with 100k but it came with the code P1273. The guy I had traded for had purchased 2 oxygen sensors and said all I did was have to put them in to fix the code, so I did the deal.

I had gone to change the sensors and they were both downstream sensors. So I bought the correct one and changed it and the code came back after clearing it.

So I searched for a solution on the forum and found the Nissan bulletin for P1273.

-Faulty Air fuel ratio (A/F) Sensor 1 Bank 1
-Air fuel ratio (A/F) Sensor 1 Bank 1 harness is open or shorted
-Air fuel ratio (A/F) Sensor 1 Bank 1 circuit poor electrical connection
-Fuel pressure
-Faulty Fuel injector
-Faulty Air Flow Meter

I then started checking for vacuum leaks under the hood and found some issues with the aftermarket CAI.
So parts are cheap on Ebay so I bought a new MAF sensor and OEM intake and took off the aftermarket CAI, I cleared the code(unplugged the MAF, started it, plugged it back in and cleared all the codes) and it came back again.

So I next bought new injectors, really cheap too on ebay and new gasket kit for the intake manifold and the aftermarket spacer,new gasket. Put it all back together and cleared the codes and it came back.

I then bought a new fuel pump and changed that out and the code came back.

I then changed the spark plugs and the code stayed off for much longer but it eventually came back.

I did a thorough going over of the exhaust and found the flex pipe on the Y pipe had some damage but there were no leaks. Well the exhaust was going to have to be replaced in a couple years and it was ugly so I bought a true dual exhaust, a HKS copy, it is beautiful and makes my G35 sound a little like my CBR. In any case the code came back.

Finally I was reading on the forum about the noise a fuel damper makes when it is going bad and from time to time at stops I would hear a vibration that sounded like it was coming from the glove box, which was empty. The fuel dampers are the only thing in the fuel system I didn’t replace and even though the problems I was reading about were causing rich conditions I thought I would give it a shot because I thought the dampener can open and cause a rich condition the opposite may occur if it gets clogged. So I changed the right side fuel damper and cleared the code. It has been over 600 miles in about 30 days and no code has returned and I don’t hear the vibration anymore from the glovebox at stops.

 

I really appreciate your input. I've would've never guessed that to be the issue, but I think Im having the same problem. I will update when I see how it goes

 

It's pretty obvious when the damper goes out, you'll head a fairly loud "thumping" sound coming from your glove box area.