P2A00 & P0300 Misfire
 

Hey guys ive made a thread before and i am still stumped. I have had a P2A00 code since installing my CAI's, since the weather changed here in NY to winter (30's) i have started throwing a P0300(random multi cylinder misfire). I am really stumped as to what to do, my short term fuel trims look good and i don't see an noticeable vacuum leaks. I'm assuming these codes are related through fuel or intake problem but I cant find the problem.

Does anyone have an idea of where too start or a common problem.

Any help is appreciated so i dont keep beating my head against the wall

That's a slow responding O2 sensor code, bank 1, sensor 1.

It could be:

1. Dirty/Bad MAF sensor or wire issue.

2. Damage to sensor or wire on the primary bank 1 O2 (what the code actually means).

3. Something screwy related to the CAI diameter being different from OEM or possibly not being clamped down well enough (MAF's are VERY sensitive to vibration and airflow tumble effects on this car).

Try swapping or cleaning the MAF's. The the problem doesn't move/go away, look into replacing the Bank 1 primary O2.

Ditto on the dirty MAFs. Good luck.

Instead of starting another thread I rather join in here, my Z just recently threw the code P0300. I just want to know if I can still drive the car until I fix the problem? Also on this code all I have to do is replace the O2 sensors? Or should I take it to dealer? My intake is fine no leaks or anything.

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Bump for Help^

You have a bad MAP sensor and that is probably causing intermittent misreads and incorrect fueling, resulting in a random lean miss and thus the P0300 code. The O2's do not appear to be related here, and seem to be working fine.

In short, yeahhhh... you should be fine at low to moderate load (i.e., normal driving) I wouldn't push it to redline until you get the MAP sensor replaced, as it's not clear how lean you are running when you miss (presumably not enough to be out of range on the fuel trims, but, still best to solve the problem before pushing it).

There was just a thread on this with details where it's located etc in the intake manifold, but if you are still under the drivetrain warranty, I would just take it to the dealer.

Ok, Thx! Very helpful man ill just go dealership but till monday I think they're closed sundays :/

Yea, thanks for the response, i have previosuly swapped MAF sensors and code came back same bank. Like i said i smoke tested the intake, no leaks found. My next try is to swap the A/F sensors and hope the code moves otherwise, im lost. Thanks for the help ill update you as soon as i find time to do the swap.

I'd just go ahead and order an O2 sensor. That's almost definitely it.

Probably a break on the wire somewhere -- I had that happen to one of my secondary O2's once. Sensor itself was ok, but the wire had a small break in the insulation on it. Swapped out the sensor and problem solved.

Good luck!

BTW, do not clear the codes -- let them see the bad MAP sensor code.

Also, just to clarify in case you aren't familiar with the various sensors involved: it's the MAP (manifold absolute pressure) sensor and not the MAF (Mass Air Flow) sensor -- two different sensors with similar acronyms ;) -- and absolutely not the the O2's.

Yea I didn't clear them and I was the one that made that thread about the MAP sensor whoch should help some ppl out in the future, I had cleaned it before with Maf Cleaner but no luck atall today I plan going to the dealer and getting it fixed I just hope I'm under warranty seeing as I'm at 69k miles but I don't remeber if I bought the extended warranty I hope they'll be lenient and understanding. And to Op hope everything works out for ya man.

Hmmm.. you may be out of warranty... good luck!

I went but they're close to closing so ill be there tomorrow morning. man I'm so freaking GRATEFUL I got extebded warranty at 75k miles WOOO!! They also told me my vehicle was a recall for the steering lock and that maybe my map sensor can be waranted but they're gonna have to run a diagnostic that costs me $105. Will update soon.

That "diagnostic" is plugging in a Consult III... :shakes head:

Well, at least the sensor and labor to swap it out will be covered.

QUOTE=Jordo!;2575786]That "diagnostic" is plugging in a Consult III... :shakes head:

Well, at least the sensor and labor to swap it out will be covered.[/QUOTE]


So turns out that my MAP sensor was fine and that my ECM was "Unprogramed", so they reprogramed my ECM and my car is running great so far. I checked my PLX Kiwi and this came out as a permanent code and I checked my AFR on my Kiwi and when I go WOT the AFR is at 12.7 than when before when I had the issue it was 13.4. Don't if that's bad or good but I know my Z feels better than before.

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Yeah... U1024 is not a good code it means when they reflashed your ecm it lost it's ability to communicate with the vvel control module, IT is a CAN line communication error code, take it back ASAP. Show him the code on your reader and watch him read your codes and refuse to pay for the diagnostic since it happened after they worked on it. You can tell him it should be around page EC-156 in the FSM.

Dammit and here I thought it was fixed ok ill be sure to go back and see what happens, worst case scenario am I looking at purchasing a New ECM?

Ok I'm really lost, system was smoke tested, no leaks. Replaced the bank 1 sensor 1 a/f sensor again with denso part. Codes came back. My short term fuek trim in that bank is off the charts, indicating a lean conditoon. I can't find a lean condition anywhere. really am lost.

disconnect the sensor and the ecu harness and check the wires for a short, procedure is in the factory manual. If you don't have the manual download it, then follow the instructions on page EC-476 through EC-479 to the letter, don't leave any steps out. When you need to clear the short term fuel trims a battery reset will work. If you already smoke tested the intake you have one of the hard steps out of the way. If that doesn't fix your problem then come back. Too many dealer techs don't follow the damn manual. you don't happen to have the old sensor to check and see if it shorted and fried the o2 controller in the ecu do you? Too many dealer techs don't inspect a part they replace to see if it was actually broken or, if it may have fried something else.

Thanks man no I actually never did check that sensor, my only concern is why am I throwing a random miss with high fuel trims. Could the CAI's be causing that in one bank only? I will download that manualand go from there I actuslly have time now that she's off the road for the winter.

Yeah just follow the manual. After you go through the o2 code and it still doesnt work then you get to go through the p0300.

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Which intake do you have?

His problem is most likely unrelated to his intake.