Multiple Cylinder Misfire P0300

solidus

Honestly the car will throw wierd codes from time to time and as hard as you try to chase them , like others here have said ; they'll just go away and pop up randomly just to mess with you. You can chase it with money and parts or be meticulous and wade through the myriad of possible causes and maybe get lucky. Good luck chasing it.

Dreezy562

Usually happens to me in the cold weather and goes away when it warms up. Common problem with intakes.

Smashley

This code pops up on me only when the weather is cold after the 1st start of the day. I clear it and have had 0 issues. Happens 3/10 cold starts

Nick370

My does the same thing, the colder it is, the more likely this code comes on. I erase it and it doesn't come back on until another cold start, usually...

I think Id rather just erase it as it comes on than try to track it down, chalk it up to cold weather until I get a more specific code

SouthArk370Z

It sounds like all the obvious stuff has been checked. I'd head to the FSM (link in sig), see what all can trigger a P0300 (or other misfires), and check what I haven't already checked. YMMV

Edit: I'd also check and see if there were any updates for my ECM (and BCM and TCM while I was at it).

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Spotondl

My 2010 Nismo threw this code and after clearing it would come back after a few miles. There was an actual misfire as well but nothing that could be isolated. Turned out a rat had made a little home in the plenum under the intake and had chewed on the fuel injector harness. Little bastard chewed through some wires right at the soft bend on the drivers side of the engine. Very well concealed. Replaced the harness, cleared the code and haven’t had an electrical issue since. Car is parked currently with the dreaded CSC failure. CMAK & SB stage 3 & we’ll be fine.


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Genosphere

So my Z threw the code a couple of weeks ago and i finally got around to checking into things. To start from the beginning I went to start up and take the car for a spin on a pretty cold day, 2*C-ish, during idle before i pulled out of the garage my foot slipped of the clutch and i stalled it out when i reached to close the door. So after maybe 5 to 10 min of driving i noticed it would not go above 2500rpm, it bopped it back down every time. Plugged my OBD and pulled the code, P0300. Got it back home disconnected the battery an came back the next day fingers crossed; nope. So after cleaning and plugging it in the Lim mode was not set at 3500, then it went to 2500 again after i checked on it another day, basically 2500 most of the time. Ill upload some pics for visual aid.





The spark plugs all look about the same, I cleaned the MAFS, disconnected each coil during run with each causing a noticeable unbalance, disconnected the battery for a while to try and clear anything. The plenum as you can see looks to have oil/gas or some residue all around the O ring, this looks odd to me. I think there maybe a vacuum leak; possibly a bad O2 sensor caused by a vacuum leak?

I have been going going off a check list off a 350Z forum:

""MUST READ IF YOU ARE HAVING THIS PROBLEM.

So my car had some issues that I starter to take care of a week ago since im selling it.

steering angle sensor - all it needed was a reset.
cam sensor - changed bank2: driver side

now for the random misfire/sputter.. this is a good check list to follow:

I first got the imfamous P0300 code.. which could be so many things!!

1. MAF. dirty or bad- buy the crc MAF cleaner spray from autozone and clean or replace or swap wiht a buddy.

2. CHECK / OR CHANGE SPARK PLUGS.

3. INJECTOR STICKING OPEN? - check spark plugs to see if you find "the black one" if you see a spark plug that absolutely looks different and completely black then the corresponding injectors needs to be replaced.

4. O2 sensors- change if you have any o2 sen codes

5. Clogged cats??-your cats might be cloggedd.. easy way to fix: take out the 2 o2 sensors that plug on to the cats. turn the car on.. if the sputtering/misfire goes away AT IDLE- then your cats are clogged. if you still have misfire at idle then your cats are ok.

6. check coil packs!- easy way to narrow down the culprit is to turn the car on, and while the car is one start disconnecting one coil pack at a time.. if the car dies down or idle changes then that coil pack that you just disconnected is OK. if you disconnect a coil pack and there is no change in the way your engine is running than that is THE PROBLEM!!.

7. vacuum leak? - check intake for vacuum leaks, you can also take off the plenum and check for oil or gas on the intake.

8. PCV valve- change it!! its only $10 on ebay. located on the pass side valve cover.

9. CHECK ALL INJECTOR/COIL PACK CONNECTORS AND HARNESS.

10. MAKE SURE TO CONNECT THE RIGHT CONNECTOR FOR THE COIL PACKS IF YOU DISCONNECT THEM.. CYLINDER 4 AND 6 GET MIXED UP.. CYLINDER 4 CONNECTOR HAS ONE SOLID GRAY WIRE AND CYLINDER 6 HAS ONE GRAY/RED WIRE.

11. bad gas can also lead to misfire.. and so can a clogged fuel filter..


MY PROBLEM ENDED UP BEING A BAD COIL PACK. AFTER I CHANGED ALL 6 INJECTORS AND NEW MAF, I RESET THE ECU (http://www.technosquareinc.com/350reset.htm) AND TOOK IT TO AUTOZONE TO GET THE CODES PULLED AGAIN.. FINALLY GOT P0301 WHICH NARROWED DOWN TO CYLINDER #1.. REPLACED THE COIL AND BAM!! CAR WORKS LIKE A CHARM. HERE'S THE VQ35DE CYLINDER ORDER ALSO.. AND THIS WEBSITE IS HELPFUL IN FINDING OUT WHAT THE CODES MEAN (http://nissanhelp.com/index.php)
THIS WAS A HEADACHE FOR ME AND JUST HOPE I CAN HELP OTHERS.. ALL THIS INFO WAS GATHERED FROM THIS FORUM, FROM DIFFERENT POSTS.""

Any insight or idea on the pics and info I posted would be awesome.
Thanks

Genosphere

Update

So swapped in some coils i got and now i got the "P0021." From what I have looked up so far, it dosen't look to good at this point. Somewhere someone said it could possibly be a clogged oil filter "100+ confirmations", so they say, and have see a pretty consistent confirmation on the front end timing cover's seal being blown and leaking into the cover, which make it pretty hard to tell until you pull it... Could also be one of the sensors in the timing cover or an entirely different issue.

May try to swap over my original coils and see if that changes things. First ill try swapping out the O2 sensors i guess, since there pretty easy to get to compared to everything else.

Live in Pittsburgh if anyone wants to lend a hand with the possible front end fuckery, please give me a ring.

Quicksilvers

I would try doing an oil change and brand new oil filter,replacing all six ignition coils with Genuine Nissan OEM coils,and if you replace all your 02 sensors replace them with Genuine Nissan OEM 02 sensors they are the best for our Z’s from what I have seen and will last the longest. I have seen oil filters get clogged before because of not changing your oil on time. Report back with what happens.

Genosphere

Will do friend. I'm hoping its the clogged oil filter; sitting for ruffly a week in below freezing temps with science happening down there could just be it. Tried to run the car at least once a week in the garage, but due to almost completely severing my tendon near the third metacarpophalangeal joint, I was a bit laid up.

Thanks and fingers crossed.

Update in the pm EST.

Genosphere

So:
• I dropped the oil and filter which appears to be ok; never the less it will be changed. Oil seemed a little dirty compared to how little mileage it's seen, though could just be my imagination.

•I tested the O2 sensors per a few forums and videos I watched by testing continuity across the black leads on sensor side. I'll tell you what, those sons of bitches were shitty just to disconnect, getting to the actually sensor is going to be a pain.

•Removed bumper to prep for the whole timing cover catastrophe. That's going to be a nice project...

I'll be throwing some oil and a filter on it maaaybe tomorrow to test the whole clogg filter idea and possible swap back over my original coils; might try an swap each coil out individually with one of the extra six I got if I'm feeling super patient.

All in all, I suppose progress has been made however so little that may be.

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Spooler

Oil filters don't get clogged so to speak. If the filter becomes full it will bypass the oil around the filter and do no filtering. Whoever told you that is full of crap.

Genosphere

Soo, an update...

Took a closer look at the vvt solenoid at the front an noticed some leakage and build up. So decided to pull it; well Its ****** that's for sure. Now I don't know if it was all my doing or already cracked or what ever causing the build in the pic, but never the less it's going to need replaced.

I saw some online, the vvt solenoid, $30~ $140, Nissan dealership wants $300. Any idea if Gates is a reliable part source?

https://www.sixityauto.com/gates-lef...kaAgjVEALw_wcB

Sorry forgot how to attach html onto a word.

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Edit

So talked to my buddies at the local shop and they said they just had the same code on another and replaced the solenoid and that fixed it. So fingers crossed that its this.

Quicksilvers

As far as most electronic parts on our Z’s I always recommend installing the Genuine Nissan OEM parts as they work best on Nissan/Infiniti vehicles. It’s your car you can try it if you want. The VVT solenoid is very important if you find that it is faulty or has build up and/or blockage in it definitely replace it.

Genosphere

Well for the now the problem is fixed. I swapped out the VVT cleared the codes and ran it through the gears and hit 3500+. No longer in limp mode, both codes have yet to come back, and the ruff/weird idle is gone. For now...

Still concerned with the buildup just below the VVT case cover, on the coolant hose attachment. Hopeing it's from the VVT or gasket I just replaced.

If **** happens I'll update.

So check you're VVT if you get a P0300 +/- P0021 codes.

~Small Update~
Drove it around for a little yesterday, a little spirited driving included, everything is holding up so far. My theory is it that possibly due to the cold oil and overall temp on an old part, the sudden increase in pressure caused it to fail.