Some notes that I accounted for

• Recently replaced the alternator with a shitty AutoZone one. Highly suspect this is what is causing the p2a00. Pretty sure the voltage regulator is out of spec which causes a rough idle.

• Car is a 2006 Infiniti m35, which is nearly identical in engine and drivetrain to 2005 and newer 5at G35's.

• Big note: car is upRev tuned, average a/f I recall was around 12.7 to 12.8. Also, the rev limit is set to 7200.
• From my understanding, the higher the voltage, the richer the mixture, and the lower the voltage the leaner
• Since my car has wideband sensors , the sensor in bank 2 will be twice that of bank 1.

here is the chart at WOT throttle. Big Note, the scanner is not calibrated to account for the increased rev limit from upRev, so the rpm is slightly off, all I am concerned however is if the voltages at WOT look normal. Thanks

 

O2 sensor voltage at WOT isn't what you should be looking at, watch AF at WOT and check your O2 sensors at IDLE to make sure they cycle properly within any given timeframe.

FSM spec for bank1 sensor1 O2 data is to fluctuate around 1.5v at 2000rpm.

Your scanner doesn't need to be calibrated for RPM, it reads the PID for RPM and that's where it's getting the data, literally the car telling it what the RPM is so that shouldn't be an issue (at least not one I have ever heard of, ever).

O2 sensors start to get lazy with age, you'll see this at idle though.

As for the issue with your car, how many miles are on the plugs, have you pulled them to inspect lately? Often times it's tertiary problems like oil in the spark plug well tubes that causes issues like that.

As for the bank1 or bank2, the engine is two separate HALVES, bank 1 is the right (passenger USDM) side, bank2 is the left (driver USDM) side. Fuel management is separated per half of the engine, bank2 isn't "double" bank1, it's it's own entirely separate entity. The O2 sensor reads the exhaust stream from each bank (each bank has 1 exhaust pipe via the headers, each with an O2 sensor) .

 

​​​​​​Thanks for the detailed reply, I changed my plugs to iridium IX 2 years ago with new Hitachi coilpacks, I put roughly 20000 miles on them since then. I will have to change my valve covers both for bank 1 and 2 however, both have oil seepage where the gaskets sit, and I do recall some oil leaking on the sparkplug well for the bank 2 cylinder closest to the passenger ( I can't recall the exact number). I will recheck the tubes again for leakage. I'm waiting for more reviews on CZP's aluminum valve covers until I change them out however.

Also for some reason my my obdii app is unable to retrieve AFR readings for some reason, I can get sensor 1 voltage and bank 1 and 2 fuel trims, but that's about the limit as far I know. Also by double I meant the voltage, I haven't dug extensively but I read somewhere in these forums that bank 2 voltage is double bank 1 since the introduction of wideband. For the rpm issue, when my tachometer goes to say 7100 rpm, for some reason my obdii scanner only reaches 6800 rpm. I am completely a noob in how the upRev software does changes to the ecu however

Can a rough idle cause that code popup btw? My autozone reman alternator has a tendency to flash the battery and brake light at idle, dropping the voltage from 14.8 to 12 volts and the rpm dropping about a few hundred revolutions or so for a split second. I'm pretty sure from factory these reman alternators either come with cheap voltage regulators, or the regulators are out of spec I had other store alternators do the same thing. Unfortunately I only got it out of pure convenience so I'm stuck with it for now. The used oem alternator I had previously didn't exhibit these issues and only died due to age and wear.

Regardless, I cleared the code a few times and it has returned again, so after looking into the tubes I will keep driving the car and see if any more codes decide to pop up

 

If you're ever dropping to 12vdc while the engine is running you DEFINITELY have an alternator issue.

Most towns have a local starter/alternator rebuild shop that will rebuild the OEM unit for around the same price as buying an Autozone/Oreillys remanufactured unit but TYPICALLY the quality is far superior.

Here's what I would do, disconnect the battery, clean both ends of BOTH cables, including the connections on the fusible link. Also clean up the alternator wire. Also clean up the engine bonding jumper ground wire that goes from the right side of the timing chain cover to directly below the coolant reservoir.

This ensures that it's not just a corroded wire somewhere, if you still drop below 14vdc while the engine is running then get a new alternator (or just get that one rebuilt at the local shop if you have one) because it's regulator is shot.

You can also just rebuild the alternator yourself, it's not hard AT ALL, you can probably look up a youtube video on how to do it. Normally you can pull the back housing power output stud, bolts, remove the back housing. Then you can replace the regulator by itself without needing to pull the rectifier. Or talk to your local shop about just doing a regulator replacement without replacing the bearings since those are likely brand new. Tearing it all down to do bearings is a lot more labor intensive, not difficult but it's the lions share of the work when doing a full rebuild.

 

I might go ahead and just rebuild myself, never thought of that! I went through so many alternators, from ACdelco, NAPA autoparts, and Autozone and every single one of them cause rough idle. Doesnt help these are a pain to install as there's very little clearance to attach the grounding wire. The only alternator that didnt cause rough idle were junkyard oem alternators unsurprisingly. When I get home I will upload a graph of the voltage drops caused by the alternator

 

If you have had multiple alternator failures I'm pretty sure you have a bad wire somewhere. Or a melted slot for the alternator on the fusible link. Or a bad battery.