Spark Plugs at 44k

[ftwhite]

Decided to spend some stuck at home time to replace my spark plugs. 2018 only has 44k on it (mostly local but around 1/4 longer multi day drives), but this is my third truck with active fuel management and cylinder deactivation, so I am always suspicious of fouled plugs. Truck was running OK, but idled rougher than when new. Here's the pics. Unfortunately, when moving the plugs they got mixed up (good shop help is hard to find and he reminded me I pay him nothing ). I believe the oil soaked darker one is from the right rear (passenger) spot (#8).

 

New plugs and wires are in. I'll probably run them for about 5-10k and check again to see if it is persistent. 

[Colossus]

^^^^^   That is why I tell people to change their plugs wellllll before 100,000 miles.  (Same with coolant and tranny fluid and front and rear diff and transfer case) Just because the manual and GM says they are rated for 100,000+ miles doesn't mean they really are.  But then there are the bone heads who say: "Well... I uh.. have 200,000 miles on the original plugs and never a problem..." 

[JimCost2014]

5 hours ago, ftwhite said:

Decided to spend some stuck at home time to replace my spark plugs. 2018 only has 44k on it (mostly local but around 1/4 longer multi day drives), but this is my third truck with active fuel management and cylinder deactivation, so I am always suspicious of fouled plugs. Truck was running OK, but idled rougher than when new. Here's the pics. Unfortunately, when moving the plugs they got mixed up (good shop help is hard to find and he reminded me I pay him nothing ). I believe the oil soaked darker one is from the right rear (passenger) spot (#8).

 

New plugs and wires are in. I'll probably run them for about 5-10k and check again to see if it is persistent. 

Are you using/losing any oil?

 

Someone else just started a thread on his truck going through 1.5 quarts of oil in X amount of miles. Just curious, with the one plug being pretty "oily". 

Edited November 16, 2020 by JimCost2014

[newdude]

Hmm.  The oily one, if pulled from #8, is a non AFM cylinder.  I wouldn't be surprised to have seen that plug come from cylinder #7 the driver rear (an AFM cylinder), as the LS 5.3 use to fowl those out often.  Interesting you got that from #8.

Edited November 16, 2020 by newdude

[ftwhite]

Thanks for that AFM info, good to know. 

Yeah, I wish I hadn't lost track of where they came from. 

I don't lose oil that I notice on the stick.

I did have a clogged oil catch can for a few months. I wonder if the darker plug came from the intake closest to the PCV hose?  

[14burrito]

Did you install the same plugs in?

 

Been thinking of going to a heat range 6 vs the OE 5 (being that I live in AZ).

[CamGTP]

Where you live really has nothing to do with heat range temp on the plugs. If you have no power adders and have no need for the electrode to stick out less, don't run anything other than the stock heat range.

[Black02Silverado]

Interesting to see that at 44k miles. No need to change heat range.  Let us know how it runs with the new plugs.

[MY164X4]

Good write up thanks.

 

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[royalkangaroo]

Great post!  I just had a random misfire in cylinder 5 earlier this week.  Was one and done, and hasn’t done it since, however I just picked up all new plugs and wires anyway.  Curious to see how mine look at 70k miles.

[MY164X4]

The OEM plugs come pre-gapped (most likely at .040 in).

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[Colossus]

check the gap anyway. 

[royalkangaroo]

I just picked up a set of AcDelcos from Advance Auto and 7 out of 8 have some form of corrosion on the ground electrode weld. Am I crazy to return them and ask for completely clean ones?





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[Sir Dan]

I would not install pre rusted plugs but that's just me. Seems like something went wrong with the welding there 

[Colossus]

And the gap is off.