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Multiple misfires - P0300 :(


Kernow

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Hey guys,

 

My 05 Z has just thrown up a P0300 error code (checked with torque app) and she is showing the check engine light. She is running really rough and clearly mising on idle.

 

Looking through past topics it sounds like it is likely to be either the injectors, spark plugs or coils??? She had new spark plugs last year from a Nissan dealership but to my knowledge has never had the coils checked or replaced.

 

I am planning on driving her a short distance to the nearest garage but I wanted to check with you guys whether, first of all driving would do any harm with the missing? and if it might be worth giving her a dose of injector cleaner as a shot in the dark?

 

She has been fairly rough to start the last 6 months or so and sometimes she chockes and dies when I start her up, could this be related?

 

I would appreciate any help and if there are a few simple checks I can do before taking her to the garage I will give it a go, though I am no mechanic...

 

Cheers guys and gals,

 

Kernow

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http://www.350z-uk.com/topic/61659-p0300-misfirecoilpackinjectors/

 

I had the same issue quite some time ago, a non specific error code relating to a "miss-fire". Eventually I would receive a nominated Cylinder miss-fire, so I could then swap out the offending coil pack. Not to say your issue is related, although my guess is that Coil Packs are your issue.

 

Taking the advise from Alex in the above link should help identify the offending coil pack. You can get used coil packs from the usual suspects, especially as new ones are NOT cheap.

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http://www.350z-uk.c...lpackinjectors/

 

I had the same issue quite some time ago, a non specific error code relating to a "miss-fire". Eventually I would receive a nominated Cylinder miss-fire, so I could then swap out the offending coil pack. Not to say your issue is related, although my guess is that Coil Packs are your issue.

 

Taking the advise from Alex in the above link should help identify the offending coil pack. You can get used coil packs from the usual suspects, especially as new ones are NOT cheap.

 

Thanks Wasso,

 

How would I go about finding the offending cylinder/cylinders? I've only got this one error code.

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£35.99 form euro car parts mate just checked on line

 

you could buy one and swap it one at a time till the miss-fire stops if you cant identify which one it is

Edited by gsexr
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My car has been suffering from the same issue, unfortunately it worked out to be something worse than a bad plug or coil.

 

As other have said, to identify the missfiring cylinder(s) you can unplug each coil pack one at a time while the engine is running. If the engine noise changes and it begins to run even rougher, then that cylinder is working. If you unplug one and there is no change, that cylinder is missfiring. They aren't that accessible so you'll want to remove your strut bar and engine cover first. Remember to release the tension on the strut bar first :p

 

Once you have identified the missfiring cylinder(s) you can swap the coil pack from it with a known working pack. If you start the engine and the fault has jumped to the previously working cylinder, then the coil pack is bad. If there is no change you can swap your spark plug and do the same.

 

If there is still no change you can swap the fuel injector from the faulty cylinder(s) with known working injectors. You'll need to remove the plenum to do this though.

 

If after all of that the fault remains on the same cylinder(s) then you might want to do a compression check. This is where my problem was, cylinder 4 failed the compression test. It failed a wet compression test too which would indicate a valve problem, its in a garage at the moment and i'm looking at either a head swap or a new engine.

 

Cheers

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This issue seems to be catching! Both Spatt and myself have had exactly the same issue at the same time this past week. Both turned out to be a dodgy coil pack.

 

Matt (Spatt) just replaced all 6 with 6 known good ones from ZMANALEX whereas I followed the suggestion above. Let the car get upto working temperature and start to miss fire/lumpy idle. Unplug (from the connector) each coil pack one by one. If you unplug a 'good' one, the revs will drop noticeably. When you unplug the 'bad' coil pack, there will be no change.

 

It's a bit of a PITA to do, as it's just fiddly. But a little patience and it's an easy DIY job with basic spanner skills.

 

Just remember to plug your MAF back in once done, eh Spatt.......? :lol:

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Thanks for the help guys,

 

Turns out the coil in cylinder 1 is the issue... or at least one of the issues as I didn't bother checking the coils under the intake.

 

Pedro, sorry to hear yours is down on compression, hope you get it sorted out ok.

 

Now to pick up a working coil :)

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She is purring like a kitten again, thanks Lee for hooking me up. I've got a faulty coil pack now so anyone know of someone who refurbs? (I'm assuming that more coils will go in the near future)

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  • 3 months later...

I'm having the same issue right now. P0300 random misfire. Checked the coils and replaced the sparks, still misfiring. Compression on all 6 cylinders is fine. Being told there could be a timing issue.

 

Anyone had timing issues from this code and if so what should I do next?

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I'm going to try changing the plugs this afternoon. I'm going to get them from euro car parts however they list 1 ngk £11.99 1 ngk DENSO £14.99 and 1 ngk DENSO £17.99. My car is a 04 with a scorpion exhaust and K&N panel filter. Any idea what plugs into need? ? ?

 

Sent from my SM-G930F using Tapatalk

 

 

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Have you confirmed 100% what the problem is yet?

 

I replaced plugs, packs and injectors when i had the same issue before i had nailed the source of the problem, could have saved myself some cash.

 

How many coils/packs would be replaced for that £350? Did you ask which cylinders were effected? When i asked nissan for six of each they wanted over a grand.

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Yeah I've taken the car to the garage and got the random misfire code. So the garage thinks spark plugs and coils. So my plan is a new set of plugs from tarmac ( cheers stylz these look a good buy). Then I'm going to buy one coil. Change the plugs and hope it's only one coil that is the problem. Ngk coils are £65 each so £390 for 6 or I can get some from Clark motorsport for £50. Hope that'll sort it and with any luck it'll be done for about £115. That'll teach me for having a spirited drive with an mr2!! It happened 1 miles later the next day!

 

Sent from my SM-G930F using Tapatalk

 

 

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Yeah I've taken the car to the garage and got the random misfire code. So the garage thinks spark plugs and coils. So my plan is a new set of plugs from tarmac ( cheers stylz these look a good buy). Then I'm going to buy one coil. Change the plugs and hope it's only one coil that is the problem. Ngk coils are £65 each so £390 for 6 or I can get some from Clark motorsport for £50. Hope that'll sort it and with any luck it'll be done for about £115. That'll teach me for having a spirited drive with an mr2!! It happened 1 miles later the next day!

 

Sent from my SM-G930F using Tapatalk

 

 

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