Need help. Misfire on 3

martelds · 06-21-2021, 03:54 PM

I have a 2016 2SS M6. I just added long tube headers and X-pipe. I removed the cats. I got it all back together and I still need to have it tuned. But before I can get it tuned I'm having an issue with a misfire on cylinder3. So far I swapped out all spark plugs on the drivers side. 1,3,5 and 7. I had some spark plugs wires that were touching on the headers so I swapped those out as well with ones that completely clear the headers. But I'm still getting misfire on cylinder 3. I found a post where someone said they had the same issue after installing long tube headers they had choked injectors and ran a gallon of SeaFoam and then a full tank of 93. This helped him. It's hard to believe I have a bad coil pack, they were fine before I put on the headers. But at this point I'm looking for any good suggestions.

s346k · 06-21-2021, 04:38 PM

if it happened immediately after you did work on the car, there's a 99.99999% chance it is something you did. thoroughly check all electrical connections, vacuum sources etc. its possible its an injector but highly unlikely.

martelds · 06-21-2021, 04:52 PM

I certainly agree it's something I did. But the question is what? I didn't have to remove any vacuum hose. Just spark plugs, wires and PCV hoses. I'll take a step back and go over it all again. I don't think it's a bad injector or coil pack. But I'm at a loss.

s346k · 06-21-2021, 05:12 PM

pcv hose is a vacuum hose.

id double and triple check everything. it's something dumb and will most likely be a very easy fix. you could swap coils and see if the misfire follows if you think that's the issue. i had a cylinder so lean it didn't even look like it was firing bc of a bad injector. car never misfired, most likely bc it is on ethanol.

martelds · 06-21-2021, 05:37 PM

Thanks for the tips. I know the PCV is a vaccum hose, maybe I didn't get a good seal when I connected them back. It has to be something simple, it just has too.

ctrlz · 06-22-2021, 08:34 AM

Hook up a scan tool and check fuel trims. If vacuum leak affecting one cylinder, you should see attempt at compensation through fuel trims.
I doubt that.
Try swapping coil packs with cylinder 3 and see if misfire moves. I suspect electrical problem.
Also check any rerouting of spark plug wires in case you got things close enough to get a misfire though induction.

avalonandl · 06-22-2021, 08:54 AM

Broke/cracked a spark plug?

Spaceme1117 · 06-22-2021, 09:01 AM

Quote:

Originally Posted by avalonandl

Broke/cracked a spark plug?

That's what I was thinking also.

I would check the plug again even though you said you changed it.

martelds · 06-22-2021, 01:47 PM

Thanks for all the help. I swapped the coil pack and same problem. I am super sure it's not a spark plug or wire as I replaced all sparks plugs on drivers side, 1,3,5 and 7 and I even replaced the replacement spark plug wires. I suspect some kind of vacuum leak. I went ahead a bit the bullet and took it to the dealer to diagnose this issue. I'll post their findings when they get back to me.

martelds · 06-25-2021, 11:57 AM

Ugh! Ok it's turns out I either broke # 3 Spark Plug or it was bad when I installed it. I didn't think it was plug 3 since I had replaced it, but that what the problem was. Thank for the help.

s346k · 06-25-2021, 06:28 PM

good to know. i've been bitten by the same issue.

06-21-2021, 03:54 PM	#1
martelds Go Arizona Cardinals Drives: 2006 GMC Duramax 2500 HD, 2016 2SS Join Date: Sep 2015 Location: Arizona Posts: 321	Need help. Misfire on 3 I have a 2016 2SS M6. I just added long tube headers and X-pipe. I removed the cats. I got it all back together and I still need to have it tuned. But before I can get it tuned I'm having an issue with a misfire on cylinder3. So far I swapped out all spark plugs on the drivers side. 1,3,5 and 7. I had some spark plugs wires that were touching on the headers so I swapped those out as well with ones that completely clear the headers. But I'm still getting misfire on cylinder 3. I found a post where someone said they had the same issue after installing long tube headers they had choked injectors and ran a gallon of SeaFoam and then a full tank of 93. This helped him. It's hard to believe I have a bad coil pack, they were fine before I put on the headers. But at this point I'm looking for any good suggestions. __________________ 2015 Nissan Murano SL with Tech Package 2006 Lifted GMC Duramax 2500 HD. Lot's of custom parts! 2016 2SS Garnet Red 2SS,6 Speed, NPP, MRC, Adrenaline Red interior, Black Rally Stripes, NAV, Sunroof, Corvette Z51 Black Wheels, Black Front Fascia, aFe / PFADT Suspension Lowering Springs, Black High Rise Rear Spoiler. High flow headers, E85, Roto-Fab Cold Air, MSD Atomic AirForce Intake. aFe / PFADT Front & Rear Sway Bar. Pushing 520 to the Rear Wheels

06-21-2021, 04:38 PM	#2
s346k Drives: like an old lady Join Date: Jun 2012 Location: indiana Posts: 2,395	if it happened immediately after you did work on the car, there's a 99.99999% chance it is something you did. thoroughly check all electrical connections, vacuum sources etc. its possible its an injector but highly unlikely. __________________ 2016+ camaro: everyone’s first car

06-21-2021, 04:52 PM	#3
martelds Go Arizona Cardinals Drives: 2006 GMC Duramax 2500 HD, 2016 2SS Join Date: Sep 2015 Location: Arizona Posts: 321	I certainly agree it's something I did. But the question is what? I didn't have to remove any vacuum hose. Just spark plugs, wires and PCV hoses. I'll take a step back and go over it all again. I don't think it's a bad injector or coil pack. But I'm at a loss. __________________ 2015 Nissan Murano SL with Tech Package 2006 Lifted GMC Duramax 2500 HD. Lot's of custom parts! 2016 2SS Garnet Red 2SS,6 Speed, NPP, MRC, Adrenaline Red interior, Black Rally Stripes, NAV, Sunroof, Corvette Z51 Black Wheels, Black Front Fascia, aFe / PFADT Suspension Lowering Springs, Black High Rise Rear Spoiler. High flow headers, E85, Roto-Fab Cold Air, MSD Atomic AirForce Intake. aFe / PFADT Front & Rear Sway Bar. Pushing 520 to the Rear Wheels

06-21-2021, 05:12 PM	#4
s346k Drives: like an old lady Join Date: Jun 2012 Location: indiana Posts: 2,395	pcv hose is a vacuum hose. id double and triple check everything. it's something dumb and will most likely be a very easy fix. you could swap coils and see if the misfire follows if you think that's the issue. i had a cylinder so lean it didn't even look like it was firing bc of a bad injector. car never misfired, most likely bc it is on ethanol. __________________ 2016+ camaro: everyone’s first car

06-21-2021, 05:37 PM	#5
martelds Go Arizona Cardinals Drives: 2006 GMC Duramax 2500 HD, 2016 2SS Join Date: Sep 2015 Location: Arizona Posts: 321	Thanks for the tips. I know the PCV is a vaccum hose, maybe I didn't get a good seal when I connected them back. It has to be something simple, it just has too. __________________ 2015 Nissan Murano SL with Tech Package 2006 Lifted GMC Duramax 2500 HD. Lot's of custom parts! 2016 2SS Garnet Red 2SS,6 Speed, NPP, MRC, Adrenaline Red interior, Black Rally Stripes, NAV, Sunroof, Corvette Z51 Black Wheels, Black Front Fascia, aFe / PFADT Suspension Lowering Springs, Black High Rise Rear Spoiler. High flow headers, E85, Roto-Fab Cold Air, MSD Atomic AirForce Intake. aFe / PFADT Front & Rear Sway Bar. Pushing 520 to the Rear Wheels

06-22-2021, 08:34 AM	#6
ctrlz Drives: 2017 2SS, 50th pkg, M6, MRC, NPP Join Date: Jan 2016 Location: Ocean City, NJ Posts: 3,177	Hook up a scan tool and check fuel trims. If vacuum leak affecting one cylinder, you should see attempt at compensation through fuel trims. I doubt that. Try swapping coil packs with cylinder 3 and see if misfire moves. I suspect electrical problem. Also check any rerouting of spark plug wires in case you got things close enough to get a misfire though induction.

06-22-2021, 08:54 AM	#7
avalonandl Drives: 2019 ZL-1 Join Date: Feb 2009 Location: Troy, MI & Naples, FL Posts: 2,019	Broke/cracked a spark plug? __________________ 2019 ZL-1 Acquired 4/23/21 at 6300 miles. Riverside Blue, A10, PDR. Traded in 2017 2SS with 6M and 32k miles. Continental Extreme Contact Sports. Now has 10,000 miles... 2012 Yukon XL Denali w/ 6.2 AWD

06-22-2021, 01:47 PM	#9
martelds Go Arizona Cardinals Drives: 2006 GMC Duramax 2500 HD, 2016 2SS Join Date: Sep 2015 Location: Arizona Posts: 321	Thanks for all the help. I swapped the coil pack and same problem. I am super sure it's not a spark plug or wire as I replaced all sparks plugs on drivers side, 1,3,5 and 7 and I even replaced the replacement spark plug wires. I suspect some kind of vacuum leak. I went ahead a bit the bullet and took it to the dealer to diagnose this issue. I'll post their findings when they get back to me. __________________ 2015 Nissan Murano SL with Tech Package 2006 Lifted GMC Duramax 2500 HD. Lot's of custom parts! 2016 2SS Garnet Red 2SS,6 Speed, NPP, MRC, Adrenaline Red interior, Black Rally Stripes, NAV, Sunroof, Corvette Z51 Black Wheels, Black Front Fascia, aFe / PFADT Suspension Lowering Springs, Black High Rise Rear Spoiler. High flow headers, E85, Roto-Fab Cold Air, MSD Atomic AirForce Intake. aFe / PFADT Front & Rear Sway Bar. Pushing 520 to the Rear Wheels Last edited by martelds; 06-22-2021 at 05:36 PM.

06-25-2021, 11:57 AM	#10
martelds Go Arizona Cardinals Drives: 2006 GMC Duramax 2500 HD, 2016 2SS Join Date: Sep 2015 Location: Arizona Posts: 321	Ugh! Ok it's turns out I either broke # 3 Spark Plug or it was bad when I installed it. I didn't think it was plug 3 since I had replaced it, but that what the problem was. Thank for the help. __________________ 2015 Nissan Murano SL with Tech Package 2006 Lifted GMC Duramax 2500 HD. Lot's of custom parts! 2016 2SS Garnet Red 2SS,6 Speed, NPP, MRC, Adrenaline Red interior, Black Rally Stripes, NAV, Sunroof, Corvette Z51 Black Wheels, Black Front Fascia, aFe / PFADT Suspension Lowering Springs, Black High Rise Rear Spoiler. High flow headers, E85, Roto-Fab Cold Air, MSD Atomic AirForce Intake. aFe / PFADT Front & Rear Sway Bar. Pushing 520 to the Rear Wheels

06-25-2021, 06:28 PM	#11
s346k Drives: like an old lady Join Date: Jun 2012 Location: indiana Posts: 2,395	good to know. i've been bitten by the same issue. __________________ 2016+ camaro: everyone’s first car

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