I have a misfire / spark plug issue - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

nyrfan · 04-19-2018, 06:24 AM

Hello all, it’s been a long time! Last week I started having an issue on my L99 with a very rough idle, misfires and backfiring. Yesterday I decided to pull the plugs and while the tips all seemed OK, the threads on 6 of the 8 had a lot of oil on them. See the attached picture. I’m guessing this is somehow my problem, however I’m not very mechanical. The car is six years old in November, but only has just under 13,000 miles.

Any suggestions here? What should I do or what should I be looking for? Someone mentioned to me it could be the valve cover gasket, however I don’t see any oil on the outside. And then someone also mentioned spark plug O-rings, however I can’t seem to find anything about them on the on l99.

Thanks everyone and I look forward to the replies.

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DvKillar · 04-19-2018, 09:21 AM

hmm. looks odd that the electrode seems clean, but threads have wet oil, but not the terminal! were the 6 and 8 plugs seated properly? tight?

cypressh · 04-19-2018, 09:44 AM

Is there a leak from the valve cover by chance? And if not do you see any fluid from the exh. Manifolds at all?

nyrfan · 04-19-2018, 10:06 AM

Like I said only that the treads appear to be wet, but I’m assuming oil is getting onto the electrodes as I’m getting a lot of misfire and backfires. I see no oil anywhere around the valve covers or anywhere else for that matter, only in the treads. And yes they seemed pretty solidly in there.

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cypressh · 04-19-2018, 10:14 AM

It could be possible blow by, it could also be the excess oil that is ingested through the pcv system that is routed back through the intake.

nyrfan · 04-19-2018, 11:53 AM

I don’t believe this would be blow by.

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JD555 · 04-19-2018, 12:12 PM

When you say backfire do you mean backfire into the intake manifold or an after fire in the exhaust? Backfire is usually caused by a lean condition or a valve stuck or damaged. After fire a rich condition such as lose of spark or overfuel. Weird about the oil only on the treads.

camguynj · 04-19-2018, 12:26 PM

Any CEL? As there’s oil on both banks kind of rules out both VCs leaking. Have the vc, plugs, heads ever been out before? What’s the catch can look like?

xc_SS/RS · 04-19-2018, 12:28 PM

check your valve cover gaskets. it'll just barely be leaking

nyrfan · 04-19-2018, 12:47 PM

Quote:

Originally Posted by JD555

When you say backfire do you mean backfire into the intake manifold or an after fire in the exhaust? Backfire is usually caused by a lean condition or a valve stuck or damaged. After fire a rich condition such as lose of spark or overfuel. Weird about the oil only on the treads.

BF through the exhaust. And it doesn't happen all the time. Like yesterday morning it was just a rough idle, but in the afternoon it kept popping

nyrfan · 04-19-2018, 12:48 PM

Quote:

Originally Posted by camguynj

Any CEL? As there’s oil on both banks kind of rules out both VCs leaking. Have the vc, plugs, heads ever been out before? What’s the catch can look like?

I believe the plugs came out when I had the headers done. Nothing else was removed. CC pretty empty. Also I did get a flashing CEL, which means misfire, but it went off and AZ could not read any codes other then my O2 sensors which are tuned out.

nyrfan · 04-19-2018, 12:51 PM

Quote:

Originally Posted by xc_SS/RS

check your valve cover gaskets. it'll just barely be leaking

If it's the VC gaskets, wouldn't I see oil somewhere? The engine is completely dry.

camguynj · 04-19-2018, 01:40 PM

Maybe the plug seals are bad from not being torqued to spec from when the headers where installed? It might be worth while to put in new plugs making sure they’re torqued to spec and the seat threads are dry. Then check after a day or two to see what they look like. If oil is present then you know it’s not the plug seals.

nyrfan · 04-19-2018, 02:06 PM

Quote:

Originally Posted by camguynj

Maybe the plug seals are bad from not being torqued to spec from when the headers where installed? It might be worth while to put in new plugs making sure they’re torqued to spec and the seat threads are dry. Then check after a day or two to see what they look like. If oil is present then you know it’s not the plug seals.

Anyone know the torque specs for the spark plugs?

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04-19-2018, 06:24 AM	#1
nyrfan Let's go Rangers! Drives: 13' AGM 2SS/RS L99 Join Date: Jun 2011 Location: Orlando, FL Posts: 10,742 View My Garage	I have a misfire / spark plug issue Hello all, it’s been a long time! Last week I started having an issue on my L99 with a very rough idle, misfires and backfiring. Yesterday I decided to pull the plugs and while the tips all seemed OK, the threads on 6 of the 8 had a lot of oil on them. See the attached picture. I’m guessing this is somehow my problem, however I’m not very mechanical. The car is six years old in November, but only has just under 13,000 miles. Any suggestions here? What should I do or what should I be looking for? Someone mentioned to me it could be the valve cover gasket, however I don’t see any oil on the outside. And then someone also mentioned spark plug O-rings, however I can’t seem to find anything about them on the on l99. Thanks everyone and I look forward to the replies. Sent from my iPhone using Tapatalk __________________ Soprano 4/1/00-6/14/11, Gone but NEVER forgotten! FSP tuned: 377/389 Last edited by nyrfan; 04-19-2018 at 07:19 AM.

04-19-2018, 09:44 AM	#3
cypressh Canadian Drives: 2011 Camaro 2SS/RS Join Date: Dec 2013 Location: Lumsden Saskatchewan Posts: 406	Is there a leak from the valve cover by chance? And if not do you see any fluid from the exh. Manifolds at all? __________________ 2011 Camaro SS/RS --------------------------------------------------------- The cars we drive say a lot about us.

04-19-2018, 10:06 AM	#4
nyrfan Let's go Rangers! Drives: 13' AGM 2SS/RS L99 Join Date: Jun 2011 Location: Orlando, FL Posts: 10,742 View My Garage	Like I said only that the treads appear to be wet, but I’m assuming oil is getting onto the electrodes as I’m getting a lot of misfire and backfires. I see no oil anywhere around the valve covers or anywhere else for that matter, only in the treads. And yes they seemed pretty solidly in there. Sent from my iPhone using Tapatalk __________________ Soprano 4/1/00-6/14/11, Gone but NEVER forgotten! FSP tuned: 377/389

04-19-2018, 10:14 AM	#5
cypressh Canadian Drives: 2011 Camaro 2SS/RS Join Date: Dec 2013 Location: Lumsden Saskatchewan Posts: 406	It could be possible blow by, it could also be the excess oil that is ingested through the pcv system that is routed back through the intake. __________________ 2011 Camaro SS/RS --------------------------------------------------------- The cars we drive say a lot about us.

04-19-2018, 11:53 AM	#6
nyrfan Let's go Rangers! Drives: 13' AGM 2SS/RS L99 Join Date: Jun 2011 Location: Orlando, FL Posts: 10,742 View My Garage	I don’t believe this would be blow by. Sent from my iPhone using Tapatalk __________________ Soprano 4/1/00-6/14/11, Gone but NEVER forgotten! FSP tuned: 377/389

04-19-2018, 09:21 AM	#2
DvKillar Drives: 2015 Chevy Camaro 2LS Join Date: May 2017 Location: MWC, OK Posts: 815	hmm. looks odd that the electrode seems clean, but threads have wet oil, but not the terminal! were the 6 and 8 plugs seated properly? tight?

04-19-2018, 12:12 PM	#7
JD555 Drives: 2014 2SS RS, 6 sp man Join Date: Feb 2016 Location: Marlton, NJ Posts: 461	When you say backfire do you mean backfire into the intake manifold or an after fire in the exhaust? Backfire is usually caused by a lean condition or a valve stuck or damaged. After fire a rich condition such as lose of spark or overfuel. Weird about the oil only on the treads.

04-19-2018, 12:26 PM	#8
camguynj Drives: '13 SS/RS LS3 BRM Cammed NPP Join Date: Jan 2013 Location: NJ Posts: 3,812 View My Garage	Any CEL? As there’s oil on both banks kind of rules out both VCs leaking. Have the vc, plugs, heads ever been out before? What’s the catch can look like?

04-19-2018, 12:28 PM	#9
xc_SS/RS Drives: 2010 Camaro SS/RS Join Date: Mar 2014 Location: somewhere in MD Posts: 4,883	check your valve cover gaskets. it'll just barely be leaking __________________ 2010 2SS/RS Z/28 intake, NW, FAST 102, speed engineering LT's, some exhaust, ATI -10% pulley, GM flex fuel injectors, DSX flex fuel sensor, MGW shifter, HP Tuners, some suspension work, stickers and a little weight loss. 12.63 @113.53

04-19-2018, 01:40 PM	#13
camguynj Drives: '13 SS/RS LS3 BRM Cammed NPP Join Date: Jan 2013 Location: NJ Posts: 3,812 View My Garage	Maybe the plug seals are bad from not being torqued to spec from when the headers where installed? It might be worth while to put in new plugs making sure they’re torqued to spec and the seat threads are dry. Then check after a day or two to see what they look like. If oil is present then you know it’s not the plug seals.