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2015 Equinox LT 2.4L AWD
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Discussion Starter · #1 ·
Two months after replaced the spark plugs I pull them out because my daughter told me that the car shakes a little at times when starting it up in the morning. I knew the plug that I installed inside the third cylinder was not gapped correctly. It was about 0.030 instead of 0.035 that the spec called for. Rockauto says DO NOT GAP, so I installed as I have received them.

Why the carbon buildup is worst then the plugs that I removed which had 93,111 miles on them?

I pull them out last week and gapped the third plug. Need time to tell whether the shaking is gone or not....

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'16 Equinox LTZ AWD 3.6
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Did you use AC plugs? My Tahoe did not like NGK's, idle was rougher, pulled them out and put the AC plugs in and it runs better. And I swear by NGK in all my powersports engines. Only OEM plugs in my vehicles now.
I would change the bank 1, sensor 1 O2 sensor also at that mileage as it controls fuel trims.
 

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Discussion Starter · #3 ·
Thanks John. I use OEM parts only. Thanks for the advise, I will look into the O2 sensor, I only worry that I have difficulties removing the old parts because of rust or age!

I need to remove the engine mount on the Torrent to access the transmission dipstick on Thursday because it shudders when accelerating between 45 and 60 miles. It won't shudder below 40 and above 65. I had to use my foot to undo the center bolt that holds the mount. The ATF only 4 years old and still pink. Don't know why it does that!!!
 

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2011 Equinox 1LT V6 3.0L FWD 179k miles
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@superdave : I'm gonna guess there's something else going on because ... can a spark plug gap really be accurately set to eliminate an "error" of only (5) 1000'ths? I don't think so.

Also, while I'm no mechanic, based on my experience, I wouldn't get too concerned about "carbon buildup" on Plugs. I've got almost 180,000 miles on my still-factory-original plugs and none of them are mis-firing. Whenever I finally get around to pulling them out, I'm sure they'll look even worse than any of yours ... but apparently, that doesn't matter.

What probably does matter is the shape of the Center and Ground Electrodes. In your "Before" pictures, all the Ground Electrodes appears to have "buildup" on them (which is probably dynamically changing the Gap), and the Center Electrode of #2 seems to be in the worst shape of all of them! Maybe something unique is going on in that Cylinder?
 

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Discussion Starter · #5 ·
@superdave : I'm gonna guess there's something else going on because ... can a spark plug gap really be accurately set to eliminate an "error" of only (5) 1000'ths? I don't think so.

Also, while I'm no mechanic, based on my experience, I wouldn't get too concerned about "carbon buildup" on Plugs. I've got almost 180,000 miles on my still-factory-original plugs and none of them are mis-firing. Whenever I finally get around to pulling them out, I'm sure they'll look even worse than any of yours ... but apparently, that doesn't matter.

What probably does matter is the shape of the Center and Ground Electrodes. In your "Before" pictures, all the Ground Electrodes appears to have "buildup" on them (which is probably dynamically changing the Gap), and the Center Electrode of #2 seems to be in the worst shape of all of them! Maybe something unique is going on in that Cylinder?
Colt, I am having a heart attack, call the ambulance now 😌. I hope this is not the case. Nothing worse then a vehicle stranded on the highway with your loved one inside and you're miles away.
 

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2011 Equinox 1LT V6 3.0L FWD 179k miles
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@superdave : I’m the only driver. It’s only me at risk...
 

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Any possibilty that plug wasn't tightened enough? Mine looked like yours at around 60k miles when I changed. At least they are super easy to replace. Could be maf dirty or 02 weak making the engine run a little off. Clean throttle body also. I don't have a lot of experience with these 4cyl gm engines, but a lot of experience with ls1s, l99s, ls3s etc. My Terrain has its own unique issue nobody can solve. Vvt solenoids can cause rough idle too, may take a bit to set off code. May be coincidence that you changed plugs and rough idle, could be leaky injector etc, so many things can cause it. I would check for stored codes to see if there is anything.
 

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Discussion Starter · #8 ·
@Rotwiler Thanks for chiming in. I torqued the plugs to 15 ft/lb when I install them and after I checked them I torqued them to 13 ft/lb. I clean the throttle body every time I change the oil. The oil change was done two weeks ago. I did clean the MAF after I checked the plugs. VVT solenoids were replaced before Christmas in 2020. There are no stored or pending codes as well. I have done whatever I could think of and try to stay ahead of the game. I haven't change the O2 sensor yet, but if it is not working it should trigger a code. It is hard to babysit the vehicles nowadays. They are like spoiled brats. 😟
 

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Discussion Starter · #9 ·
BTW, when the VVT solenoids stopped working properly on my Nox, I did not get an engine light. The motor just burning oil like no tomorrow. One day, it decided to throw the code then I changed the solenoids immediately. The oil consumption stopped right away. Go figure!
 

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I feel your pain, My 14 2.4 I bought about 3 years ago with 40k something miles. Was worried seeing 2.4 issues, but was told around 2013 issues resolved mostly. Wife wanted it for winter and liked big back seat compared to her kia optima ex-t. Was only $6,999 so we got it. After few days it stalled 15 seconds after starting every single time, hot, cold, after long drives. Replaced with oem, maf, tb, air filter, plugs, 1 O2 sensor(one on there wire was shorting out), bought generic 2 for $22 vvt solenoid as a test to see if that was issue, changed oil, filter, added big dose of pea fuel cleaner etc, pcv was completely dry. Once running it runs perfect, never a sputter or odd sound. Bought some camshaft positioning sensors, but before I installed, seen a guy on YouTube say, he had exact same issue he fought to find solution for year plus, he removed intake etc and replaced all parts I did also. He said one day he was changing oil and decided to put 6 Oz of oil thickener, bardahl no smoke he used, others in his thread put stp. 100% stopped his stall, so I was thinking, ya right. But decided why not, once I added it it did not stall for 11 months, not even once, but when I changed oil, I decided not to use it, stalled everytime, so added it again, zero stalls. I get 22mpg average, is smooth driving, no erratic idle, no tick, odd sounds at start. I added a FC219 ac Delco oem oil cap also, vents when too much pressure in engine, if you don't have one, get it, is under $13 on Amazon, can save your rear main seal and is cheap insurance. Has me stumped, but worked. Nobody as explanation why. I post this everywhere to try to see if anyone can give me insight as to why, so far nobody has any idea why it works. I used havoline full synthetic and I used valvoline EP full synthetic oil last oil change and added the bardahl no smoke and some lubegard biotech to add moly to oil. I did notice the ac Delco oil filter looked pretty beat up this time, so I went with a k&n that's a lot more sturdy. Sorry for long post, I get ocd when car issues I can't solve, especially a stall and then no codes at all is driving me crazy.
 

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2011 Equinox 1LT V6 3.0L FWD 179k miles
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@Rotwiler There are no stored or pending codes as well. I have done whatever I could think of and try to stay ahead of the game. I haven't change the O2 sensor yet, but if it is not working it should trigger a code.
I've seen Member @rbarrios use the term "lazy" O2 Sensors ... so it may be possible for an O2 Sensor to be under-performing, but still not "triggering a code".

BTW, when the VVT solenoids stopped working properly on my Nox, I did not get an engine light. The motor just burning oil like no tomorrow. One day, it decided to throw the code then I changed the solenoids immediately. The oil consumption stopped right away. Go figure!
I've never heard of this complaint, nor have I run across any proof, but maybe the Solenoids were leaking oil?
 

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2015 Equinox LT 2.4L AWD
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Discussion Starter · #12 ·
@Colt Hero Thanks. I have seen @rbarrios 's comment about lazy sensors too. Just can't take it off my mine on the timing of the carbon buildup. Why not before I change the plugs and had to ruin the new stuff. :rolleyes:
I don't understand about the VVT solenoids neither but that was happening to my Nox. It was the exhaust one that gone south, but I replaced both at the same time.
 
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