clean the maf sensor. Its the easiest to do, won't harm the maf. Buy the maf cleaner can, spray the sensor inside out very liberally. shake, air dry. do not try to dry it or touch it with anything.

other than that, another way to check bad maf is to unplug it and drive it around. if car acts normally then the sensors were bad, if it runs rough then they were fine.

 

To update my story, all I did was replaced the sensor that went out and I had to delete the code and take it on the highway right after and drive it to do this re learning thing i read somewhere on a maxima forum. Since then the code hasnt popped back up.

If you havent replaced the sensor then im not sure if this would even work.

But try deleting the code and taking it on the highway right after and keeping it at a steady 3-3.5k rpm.

 

What sensor did you replace?

 

^--- The AFR sensor on the exhaust manifold (header upstream).


At first after replacing the AFR sensor and resetting the code. The light came back on after about 2 trys every 40miles. Then I went to do more searching and found this self relearn thread for this code on a maxima forum. A member stated about some relearning thing that needed to be required. So I followed it and the code has yet to pop back up and its been 360 miles so far.

 

im having this same problem... im not so much misifiring but very slightly sputtering when i shift to 3rd and the engine is not warmed up all the way yet. the sputtering problem seems to go away when the engine is warm. ive tried resetting the code 4-5 times and it keeps coming back. it started a while back when i bottomed out on a curb pretty bad but the sputtering was before the initial cel. the car still runs about the same when the cel is on or off. im hoping i just hit the 02 sensor and either damaged the wiring or the 02 sensor itsself.

btw my mods are the 5/16 spacer, mrev2, art pipes, invidia gemini cat back, and osiris tune. any info would be awesome

 

have this problem big time with recently a high idle .

 

I have a 08 g35x and recently got both codes. Check engine light had been on then off then on again for a few weeks but car ran fine. Last week car wouldn't start just cranked, finally after 10 tries it as started but was revving up and down on its own until it warmed up then became normal again. I had noticed since cel first came on car seem to run rich, when I was attempting to start car I could smell raw gas being sent out the pipes. I had the car diagnosed at nissan near my house and the tech told me my a/f sensors bank 1&2 sensor 1 were acting erratically because I have lots of cracks in my catalytic converters. I assume this was throwing off my a/f mixture, this explains my exhaust smell of rich fumes and different exhaust tone. Here is the important part, the cats are covered by the Federal mandated emissions warranty up to 80,000 or in my case until 4/8/2016. My luck I have 75k on this car! I brought it to infiniti since nissan cant cover this and first they tried to sell me some bs but when they saw that I had done my homework and told them I wanted my cats replaced as I was covered by this warranty they said well lets check it out first then called me and told me they were getting me new cats installed free of charge. They.ordered them today and I get to drive the new Q50 for 3 days til its fixed I know this is a long reply but I want everyone to know that if you get these codes have your cats looked at, its the best $100 I have ever spent! If you're under 80k you will be covered for new cats if they are cracked. Know your rights...

 

found out i have a tuliped valve waiting for it to be put back together and will see if its better. also had a leak at my art pipe to header

 

How long you need to stay at 3-3.5k? I'm going through this now. Had a P0303 first, ECU was bad , replaced( Dealer Warranty) now the light for P2A00 comes on every two days. No leaks anywhere. thank you

 

Anyone find a solution definitive solution? I have had my tuner check for leaks, cleaned MAF, replaced Bank 1 Senor 1 (I only am throwing P2A00), did throttle relearn procedure and SES still comes on every 100-700 miles. Mods are below. I am at a loss for what it could be at this point. I disconnect the battery and my g runs like a bat out of hell for ~200 miles and then code comes on and it runs like **** (worse mileage, doesn't pull as hard). Rinse and repeat.

06 6MT <40,000 miles as of this post
MD 5/16 spacer
MREV2
Z-tube
Berk HFC
HKS catback exhaust
Uprev Dyno Tune after all parts installed

 

holy thread revival. I myself have battled the dreaded p2a0/p2a03 for the past 6 months, but I've finally got it beat as of a few weeks ago.

The most difficult thing about these codes is that it just says the computer is detecting a lean condition. So what does that mean? This boils down to the ECU reading more o2 than it is calibrated for in your upstream A/F sensor.

Here is my personal experience with these codes as it came and went in different forms. Notice is said different forms because the cause and fix for them each time was different.

Incident 1: P2a03 by itself
Exhaust leak: check your flange between header/cat and check between cat/Y-pipe. These are the most common places where a leak can cause outside air to seep UPWARDS in the exhaust stream towards your A/F sensor on the header. Yes it sounds crazy, but it happens under partial throttle conditions and all it needs is a little bit of o2 be detected repeatedly to trigger this code. My fix was a a loose exhaust bolt at the flange between my test pipe and header causing a tiny bit of o2 to slide through and causing what the computer thought was a lean condition.

Incident 2: P2a00 by itself.
Flex pipe leak: After going about a month code-free the dreaded p2a00 popped up. First thing i did was to check my exhaust flanges again since it was the cause for the last code. Nope, all flanges were tightened down and there were no leaks at any of the flanges. Upon further inspection, one of my flex pipes on the Y-pipe of my exhaust was actually leaking. The accordian pipe behind the braid was actually broken and causing the same issue as the leaky flange. My fix was to get new flex pipes welded into my exhaust. P2a00 went away immediately and never came back.

Incident 3: P2a00 and P2a03 returns
This was the most difficult code to troubleshoot of them all. The difference this time was both came back together. I went through the exact same troubleshooting thinking the issue was on the exhaust end, but it was the exact opposite. The reason why both codes came back together was because the problem was on the intake side, not exhaust side. This time it was actually my MAF sensor starting to go bad. I cleaned the MAF sensor thinking i can eliminate it as the culprit, but that was my biggest mistake. The MAF sensor wasn't completely "bad" where it would throw a code for being out of range. The thing was under-reporting the amount of air that was going into my engine. It was just off enough to cause a lean condition in both banks over time (code came on typically after 150 miles of driving).

If you can 100% confirm it is not an intake/exhaust leak. Not a MAF sensor issue, then your final problem could be fueling. If the MAF is correctly reporting the amount of air going in, but the fuel isnt getting delivered as instructed by ECU, you will also be running lean due to the lack of fuel (remember, even just a little bit!). I didnt need to go down this rabbit hole, but that would be your last option.


TLDR: check everything AGAIN.

check the injectors on the bank that is throwing the code! check your fuel trims, both short term and long term. Do they correct back towards 0 under WOT?

 

Just got a PA200 thanks for the write up. Will search on the lift at Home.

 

Got both P2A00 and P2A03 before first track run last Saturday and was running rich, erased it and and came back the next day. I suspect exhaust leak between cats and xyz pipe since it was visible from looking underneath. Thanks for the write up.