Chasing misfire

Wuero370z · 11-17-2023, 11:32 PM

Hi, I’ve been having a p0305 code for about 6 months intermittently. I used to clear the code and it would stay away for a few weeks.
I went ahead and changed all plugs and a coil pack (accidentally changed cylinder 3 not 5) and reset the ecu but code came back almost immediately. Car has a high idle but doesn’t run horribly.
When doing the spark plugs cylinder 1 plug was completely black and the coil had some soot or black dust covering it. The rest of the cylinders looked totally fine including number 5.
I’m going to buy another coil and change cylinder 5 and hope that fixes my problem but I’m wondering why cylinder 1 plug would be fried like that…. I have been getting a heavy smell of gas from time to time in the cabin and I don’t have any exhaust leaks.
The car is also twin turbo and full e85 which I daily drive and fill up on mediocre e85.

Do you think I have a clogged injector or something? Not sure why one plug would be bad but get w misfire for a different cylinder.

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Spooler · 11-18-2023, 12:00 AM

Yup, sounds like an injector issue. Pull them and have your injectors cleaned.

Tractionless · 11-19-2023, 12:04 PM

Quote:

Originally Posted by Wuero370z

Hi, I’ve been having a p0305 code for about 6 months intermittently. I used to clear the code and it would stay away for a few weeks.
I went ahead and changed all plugs and a coil pack (accidentally changed cylinder 3 not 5) and reset the ecu but code came back almost immediately. Car has a high idle but doesn’t run horribly.
When doing the spark plugs cylinder 1 plug was completely black and the coil had some soot or black dust covering it. The rest of the cylinders looked totally fine including number 5.
I’m going to buy another coil and change cylinder 5 and hope that fixes my problem but I’m wondering why cylinder 1 plug would be fried like that…. I have been getting a heavy smell of gas from time to time in the cabin and I don’t have any exhaust leaks.
The car is also twin turbo and full e85 which I daily drive and fill up on mediocre e85.

Do you think I have a clogged injector or something? Not sure why one plug would be bad but get w misfire for a different cylinder.

Sent from my iPhone using Tapatalk

What plugs and coils did you install?

Spooler · 11-19-2023, 12:09 PM

Quote:

Originally Posted by Tractionless

What plugs and coils did you install?

I installed Z1 coilpack and those things are junk. Only use OEM coilpacks and be careful where you buy them. Lots of counterfeit parts out there these days.

Wuero370z · 11-20-2023, 10:51 AM

Did hks m45hl plugs and an oem coil pack. Didn’t replace them all yet but I will. Just stupid expensive.
I’ll stay away from Z1 as much as possible, not the greatest parts imo

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11-17-2023, 11:32 PM	#1 (permalink)
Wuero370z Enthusiast Member Join Date: Nov 2018 Location: Albuquerque Posts: 358 Drives: 2013 Nissan 370z Rep Power: 6717	Chasing misfire Hi, I’ve been having a p0305 code for about 6 months intermittently. I used to clear the code and it would stay away for a few weeks. I went ahead and changed all plugs and a coil pack (accidentally changed cylinder 3 not 5) and reset the ecu but code came back almost immediately. Car has a high idle but doesn’t run horribly. When doing the spark plugs cylinder 1 plug was completely black and the coil had some soot or black dust covering it. The rest of the cylinders looked totally fine including number 5. I’m going to buy another coil and change cylinder 5 and hope that fixes my problem but I’m wondering why cylinder 1 plug would be fried like that…. I have been getting a heavy smell of gas from time to time in the cabin and I don’t have any exhaust leaks. The car is also twin turbo and full e85 which I daily drive and fill up on mediocre e85. Do you think I have a clogged injector or something? Not sure why one plug would be bad but get w misfire for a different cylinder. Sent from my iPhone using Tapatalk

11-18-2023, 12:00 AM	#2 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 13,792 Drives: 2013 Nismo 370z Rep Power: 2684392	Yup, sounds like an injector issue. Pull them and have your injectors cleaned. Tractionless likes this.

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11-20-2023, 10:51 AM	#5 (permalink)
Wuero370z Enthusiast Member Join Date: Nov 2018 Location: Albuquerque Posts: 358 Drives: 2013 Nissan 370z Rep Power: 6717	Did hks m45hl plugs and an oem coil pack. Didn’t replace them all yet but I will. Just stupid expensive. I’ll stay away from Z1 as much as possible, not the greatest parts imo Sent from my iPhone using Tapatalk