I have a 2007 (V36) G35x Sedan. I have an eBay axle back, as well as AAM resonated test pipes. Ive been getting an occasional P2A00 code, which I originally thought was a bad upstream sensor, which I then replaced both upstreams and continued to get the code. I then purchased an OBD2 bluetooth dongle and a tablet to use torque for data logging to figure out what is really going on here. From just the live data, I can tell something is off from AFR ADJ values as well as fuel trims. Both seem to show the ECU dumping fuel into bank 1, and bank 2 seems normal. My first thought was vacuum leak, so I listened all around my engine bay with a tube jammed in my ear, and all I could find is a slight hissing near the PCV valve and line, which apparently can be normal. Here and there, especially when the weather warms up, I will get this funky idle where revs will jump up and down by about ~300 rpm, voltage fluctuates by around .3 volts with each rev cycle and sometimes higher, as well as all of the lights flicking with each rev cycle. It all goes away if I simply restart the car. I also notice some bogging if im just cruising around like 30-40 mph, and then put my foot down as if to pass someone in traffic or make a yellow light, the car seems to not know what to do for a sec, rpms kind of jerk around, and then a half second later were accelerating as if nothing happened. Live data is showing me for that little Half second, the AFR leans out. Sometimes the car drives and idles completely normal, fuel trims look good and all, and other times not so much. Since ive gotten the car about 6 months ago though, fuel consumption has been absolutely horrible, around 200 miles per 20 gallon tank if im lucky (city driving though). Im going to include a log file which was just me coming back from the gym, maybe 3 miles away. Not too much highway speeds, but I did try to nail it a few times to get some good data. I would appreciate if anyone could use their expertise to possibly identify an issue in this log.

TL;DR
2007 G35x Sedan bogging under sudden acceleration, shows high fuel trims on bank 1, and sometimes has a jerky idle with fluctuating voltage
Log file attached, would appreciate some insight interpreting the data

 

bump

 

For the future you should only log important stuff, this .csv is an absolute mess and half the stuff didn't need to be there. What software did you use for the logging? Camshaft angle B2 and Mass Airflow B2 didn't log.

Your throttle position to mass air to A/F all looks pretty normal but bank1 might be a little off which corresponds with the code you're throwing, it's spending quite a bit of time pegged on the graph even though there was only a little bit of throttle applied at that time. Again it's really hard to read your data due to what was logged.

I think you should just use some traditional troubleshooting methods, pull and inspect all 6 plugs, see if any look different. Use throttle body cleaner to spray around the intake tract to see if the rpm's bog (sucking air from a vacuum leak). Check for exhaust leaks, etc.

Have you unplugged your throttle bodies? If so did you recalibrate them? Have you done an idle air recalibration? Did these problems just suddenly pop up or has it been this way for a while? Did it start immediately after installing those test pipes?

 

Hey, thanks so much for the response. This is my first time actually pulling the csv file from the data log, so for future reference ill try to play around with adding/removing some PIDS, and I also deleted a bunch of the useless columns and reuploaded the data log as an excel file, so hopefully its alittle easier to read now. I used torque pro to pull the data. I pulled all 6 plugs bout a week ago, im going to include a pic of what they looked like, and also a video inside each chamber. There was a little bit of oil on the plugs, but from what ive read thats relatively normal for a motor at 109k miles. I also noticed one of the plugs had a missing center electrode, so I replaced all 6 with brand new oem iridium plugs. The problem still persists. I cleaned TB's about 2 weeks ago without unplugging them, but still did the idle and air volume recalibrations. I saw someone post saying the 07-08 models had a bug with the idle recalibration, not allowing it to fully finish. Maybe this is the issue? but I don't know enough to look into that. I sat around my engine bay for a few hrs looking for leaks, and like I said I heard a bit of hissing from pcv line and valve, but that's also apparently normal as well. I sprayed all around the engine bay with TB cleaner, and no change in rpm, AFR, or fuel trims.

 

You should still be able to do the idle air recalibration, it's important to make sure that ALL the required parameters are met though or it won't finish.

If you want E-Z-Mode for the idle air recalibration use the Android app Nissan Datascan 3, you can use the LITE free version to make sure it connects to your car but you will need to purchase the full version for like $8 to be able to click the idle air recalibration button, takes a little bit for the recalibration to happen it's not practically instantaneous like it is for the DE engine with NDS2.

 

I did the recalibration the manual way because my bluetooth obd wouldn�t pair with the NDS3. Nothing changed still. If you guys think this is a vacuum issue i�m thinking about removing my upper plenum and inspecting it, then replacing the gasket. The weird thing is that the problem isn�t consistent. Sometimes my fuel trims sit at 0 at idle, and other times i see bank one maxed out at 25% where bank 2 is 0, and other times i see bank 1 sitting at 0 where bank 2 is maxed out. Pretty weird.

 

bump

 

Since the last post, Ive pulled my plenum and TB's, cleaned the surface that the upper manifold contacts, and replaced the gaskets for both the plenum and TB's. I also went ahead and ran some Sea Foam through my brake booster. Nothing has changed. I want to include that im getting a test fail in Torque Pro for "MID:$06 TID:$8a" Bank 1 Sensor 1. Ive been scouring the internet but cannot find what the definition for this data is, and unfortunately my obd adapter is not compatible with other applications such os OBD fusion.

 

Im also seeing some others report cracks on the welds of their HFC/TP's, as well as a possible crack where one of the bolts of the OEM Cat brace used to go. Going to check these as well.

 

Halloween smoke machine, smoke the exhaust.

Are you able to see any data for B1S1 O2? Sometimes those "test fail" things are it's just watching the rise/fall of the data and it doesn't match whatever predetermined logic the app THINKS it should be seeing.

I think it might also be time to pull your cats off and visually inspect them for any melting/damage.

 

Number 1, i don�t cats lol, I have resonated AAM test pipes. I actually was able to locate some small leaks with the test pipes both where they connect to the exhaust manifold and where they connect to the Y pipe, particularly on the bank 1 side. I�m guessing the leaks which felt small at idle are much bigger at higher rpm and especially WOT. I�m assuming this is the issue due to the fact that i�ve seen others report similar codes and issues due to cracked test pipe welds/leaking test pipes, and i�ve ordered new gaskets from Z1 to hopefully seal up these leaks. My question is this; How would a leak AFTER the upstream o2 sensors affect their readings? Also, does this mean that i�m not actually running lean, but instead my upstream o2s are just getting false readings due to the leak(s)?

 

Air/fuel is calculated solely based on the data for the upstream. However because the upstream sensor is so close to the flange that mates to the cats/test pipe then yes you could be getting a false reading if that gasket is bad. You would see it on the plugs though, they would be pretty black, yours definitely look like it's running hot. Have you smoke tested the intake too?

You might have to run a set of non-foulers on the downstream sensors but typically this isn't something that would just suddenly pop up one day, you would be having catalytic efficiency codes thrown from the beginning when you put on the test pipes.