Ignition coil browned - sign of a bigger problem?

Replacing the plugs in my '17 Sport - 65K mi. Everything went smoothly, but the center coil on the passenger side is brown/burnt. I see some browning up the ceramic of the plug vs being all white. The other 5 coils were clean and shiny. Is this just a poorly sealed plug, or might this be a sign of a bigger issue? Heading to pick up a replacement coil for peace of mind. Thanks in advance.

 

I have seen this posted recently here 2 other times. The other two had loose plugs. Was that plug tight?

 

Yeah loose plug or leak in valve cover gasket...should test the coil with a multimeter takes 2 seconds and not just replace it as nothing is better than oem.

 

Thanks for the response... plug felt as tight as the others. New plugs torqued to 15 lbs so we'll see how things go.

 

From the look of that carbon ring on a couple of threads below the gasket, l would have expected it to be loose.

 

Maybe the buildup of carbon was what made it fit tight. Does look like it was loose with blowby at some point.

 

I agree with @mattleg and @kodiakisland, that plug ain’t right.

 

My #3 coil burned out as well. I heard something about the ACIS breaking and getting lodged in the #3 intake, and the shaft falling into the #3 intake/exhaust valve area. Basically transcribed that from a picture I took of the post, i barely know what it means, so take that with a grain of salt. Also read something about an over bored cylinder... i'll try and find a picture to post of that one

 

I experienced the exact same thing today, except it was the middle on both sides for mine. 2017 TRD Offroad 4x4. Anything ever result from your experience?

 

Same. I changed mine about a month ago and both my center coils were “browned”. Not as bad as OPs but the discoloration was there. Im in a 2019 TRD off-road 4x4.