Hey all,
First time posting here since my 08 has been perfect up until recently. Hopefully someone here can point me in the right direction because I'm stumped...

To go over my issue, I have had power loss for a couple years and finally decided to do something about it.
Plus, the car has a fairly severe vampire drain that I cant find, and the typical intermittent loss of sound of the turn signal, along with the horn no longer sounding when using the remote to lock... BUT it has always ran fine, until recently. A check engine light finally came on and it pointed to an upper O2 sensor. I decided to replace a bunch more parts that are near their limit at 120k since I was under the hood anyways.

In all, I replaced:
Both Upper O2 sensors with Denso 234-9037
Both Lower O2 sensors with Denso 234-4380
(Granted I may have the numbers backwards, but those are the actual part numbers)
Both MAF sensors with Hitachi MAF0031
Replaced the O2 sensor fuse
Cleaned the throttle bodies
Cleaned the air intakes
Replaced Battery
Reprogrammed the ECU

After swapping out all of the parts, the car STILL has these issues.
The codes that come back are P0031 (O2 S1 Bank 1), P0051 (O2 S1 Bank 2), P1148 (O2 S1 Bank 1) & P1168 (O2 S1 Bank 2).
The odds of both new O2 sensors being bad is extremely low, so I either purchased the wrong part or the ECU itself is bad...
Am I using the correct O2 sensors?
Are there any other possible causes?

To add further fun, I read that common issues with a severe vampire drain is a bad ECU, so I bought a new ECU (well refurb) from Flagship One. I can swap computers, and the key works, the car ATTEMPTS to turn on, but never gets past the point where it finally starts. This is my first time trying to do a computer swap, but they advertised "Plug and Play" and i can say 100%, that is not true. Swapping back ECUs with my original and the car starts up just fine, but shows the O2 sensor errors and has the intermittent power loss issue.

Only thing I can think of that I haven't looked into yet is the fuel pump.
Any other ideas?

 

Did you ever find the fix?

 

5 different mechanics (infiniti dealer included) told me the Denso parts I ordered were correct.

I finally bit the bullet and took it to a mechanic that specializes in electrical issues. It turns out the O2 sensors were NOT correct. The 02 sensors need to be WIDE BAND.

Hope this helps