BCs350z

iTrader: (11)

what kind of driveability issues are you guys experiencing if any? I just got this code myself but to be honest, the car feels normal to me. I have headers, test pipes, and a nismo exhaust. I thought maybe i threw the code because of my mods and no tune but i may have to look more into this.

onagao

Well, I'm experiencing what appears to be substantial power loss - not sure if it's related to the code.

Definitely related to the code, however, is a power lag as the imbalance in the AFR has to settle out under WOT (after it's reached the spiraled-out-of-control phase).

turbotoy

iTrader: (17)

I have no noticeable power loss. Just an annoying CEL

mzdfc3s

iTrader: (2)

i would bet if i put the car on the dyno you would see substantial loss at certain rpm levels. when its bad it just feels like a fat b!tch. the other reason im sure this code is coming back is because i still get the burping popping exhaust which may be related to the possible exhaust valve issue mentioned earlier. im half tempted to pop the valve covers off and have a look for myself.....

SRT BRAD

Ok, this burping/popping noise you're hearing... You're sure it's coming from the exhaust or the intake? And when you feel a loss of power or when you hear the popping, do you also feel a hesitation (misfire) at the same time?

When a popping noise comes from the exhaust, that can be associated with a lean condition, (Bad O2 sensor or intake leak) but you say the fuel trim is pulling fuel. Overly rich conditions don't usually cause popping sounds. I wonder if this magnificent dealer you're taking your car to has even checked fuel pressure??

Another thing to think about is valve timing. If you're valve timing isn't correct it can cause after fire (popping) in the exhaust. I know I have already suggested the valve train issue, but it is quite difficult to diagnose over the internet, when I'm not standing next to the car to hear the noises it's making, or experience the loss of power. It also doesn't seem right that the car is making this noise and they keep giving the car back to you until the engine light comes back on.

mzdfc3s

iTrader: (2)

the popping is like a gurgling sound def from the exhaust. doesnt happen under throttle only when decelerating from mid rpms when i just begin to get back on the accelerator gently. the ecu is pulling fuel, its DUMPING fuel. this is noticed in the fuel trims, rich O2 reading, and poor fuel mpg. i dont know where else to go from here?

onagao

This is seriously the worst gremlin I've ever seen. I'm forced to use Cipher to reset my learned fuel settings every few days if I want my car to run properly. I wish somebody who knew the f***ing solution to this would chime in.

oolatec

This won't go away for me either. I tried the "MIXTURE RATIO SELF-LEARNING CONTROL" reset, and P2A03 just keeps popping up. :|

onagao

Well, I think the "clear learned fuel settings" option is different. It clears the learned ECU trimming, not just mixture ratio data. For what it's worth.

oolatec

Probably! Have you tried both of those as well?

I have a different pair of o2 spacers than what came with my HFCs... going to try those for a few days, and if I still throw this code, I'm considering putting the stock cats back on.

onagao

Wait, what code are you getting? Because the P2A00 and P2A03 codes are for the upstream O2 sensors, not the downstream ones in the cat section.

oolatec

Yes. I know... P2A03 after installing HFCs on my 2010 G37 sedan that is literally 3 weeks old.

It's been suggested that there may be a leak from the header/cat flange, but I highly doubt it.

Other suggestion:

Damaged sensor/harness - Nope

Damaged/cracked HFC - Nope. Brand new. heh

I think it was on this board... someone's Berks were cracked, and they were throwing one of these codes. They got a replacement and that fixed it.

oolatec

Well, looks like I found out what my issue was at least. The driver's side o2 sensor was loose... brought it to a shop down the street to get it on a lift, and he was able to unscrew it with just his hand. So he tightened it up, cleared the code, and I was on my way. So far I've put over 100 miles on it since I had it tightened, and no CEL, whereas before, it would pop up between 30-50 miles.

No pending codes either. Phew.

Guys, I'd really check for leaks somewhere...

onagao

Well, having removed/swapped my O2 sensors 3 separate times now, I can safely say that that is not the source of my problem. I'm glad it worked for you, though. I just wish I knew where my solution was.

onagao

Any updates? (I'm still having the same issue on my end.)

onagao

Bump again for updates....

IvoryPearl07g

I AM SUBSCRIBING!

i have been dealing with the same issues myself over the past 6 months. it all started with the fat flat sounding exhaust note, a substantial loss in power, and some bumpy acceleration at times. It developed into a horrible jerking on acceleration and would go into limp mode. The code then was P1084....Exhaust Valve Timing Control****(side story at bottom). sooo......

.....I thought i narrowed it down to the exhaust valve timing control sensors. Cause it was obviously an issue(to me atleast) with the exhaust cams being way off timing. this problem was intermittent. SO, I got new plugs for the exhaust timing sensors from a nissan dealer and replaced them all because i could replicate the sound by messing with the connections. The problem seemed to clear up.

But over time it came back gradually and i got a new code. PO420 catalyst efficiency. SO i bought GTM resonated Test pipes which guarantee no CEL. The problem is still there and it can go from a sloppy slow & loud POS to the most sexy sounding blazing fast V6 ever. I want to figure this out!!! My code now is P2A03....A/F sensor 1. sooooo.....

.....I too think that it is an exhaust leak. I have heard the newer OBD2 cars absolutely cannot run good with out the o2 sensors getting the most accurate information. And with all the aggressive driving and exhaust dragging(Im lowered) i have done over the years, im thinking a crack somewhere on the manifolds/headers or some moisture/corrosion on the plug connections. I want to follow this thread since there is a dealer replacing everything else on the car. Im going to continue to work on the smaller more obvious things since its not my daily driver. I really want to fix it, but if i know absolutely no dealer has put a TSB out on the issue, i might have to put it to stock and sell the car.







***Side story about the P1084 code....
Same issue was going on with another 07 G35 sedan vq35hr. The dealer kept replacing the exhaust valve timing sensors. After a couple months of this, the car finally blew up. Apparently something failed on the exhaust cam/solenoid. when the cam slapped over, it jumped timing and---- all the valves bent-pistons on that side had holes- the other side jumped timing-those valves bent-and those pistons cracked.

It was an absolute failure. The dealer wouldnt cover the warranty because they deemed the aftermarket air intake to of caused the problem. He had to either pay $5000 to get the car back in pieces....or $13000 to get it fixed and back to him. Needless to say he whipped the credit card out and had it fixed. So this possible outcome has been in the back of my mind.



IN YOUR REPLIES- ADD IF YOU HAVE GROUND WIRES OR NOT. Im testing a theory.

I Have sunauto ground wires and voltage stabilizer box.

turbotoy

iTrader: (17)

Found two exhaust leaks on mine. Sealed up waiting to see if the CEL returns. If it does I am going after the intake side. Also FYI my o2 sensor voltages bank1 .320 volts bank2 .870 volts

onagao

My CEL hasn't returned in over a month, but I can plug in Cipher, and it will tell me that the AFR overcorrection issue is still there. No exhaust leaks for me.

turbotoy

iTrader: (17)

I have stated what my o2 reading are at idle. When driving when you let off the throttle the mixture goes dead lean. My readings are Bank1 .900 volts and bank2 1.2 volts. I would think they should be the same with no fuel? Also after driving around for awhile my corrections between banks are closer ,almost the same going between + and -, then when I first cleared the "learned fuel".