Little background, 2008 Denali 6.2 AWD Magnuson TVS-1900, LS7 throttle body, 3.2 pulley, 7 pounds boost, LS9 cam, VVT delete, just Magnuson tune and TSP did the VVT delete. These were LS9 plugs, I believe ACDelco 41-104. It runs good for the most part. A little bit of a rough idle, which drives me crazy. I changed to NGK BR6EF plugs today. These only had a few thousand miles and are maybe two months old and put in when I put on the sc. Just hoping to get some insight from more experienced guys, any input would be great. I think my tune needs some work.

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Passenger side 2 at the bottom to 8 on the top

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Driver side 1 at the bottom to 7 on top.

Please excuse the anti-sieze, I probably went a little heavy on it.

 

Look pretty normal to me.

Maybe a little unburnt fuel, kinda see some soot but nothing huge in my eyes.

 

Look safe. It rich but the hot plug is cleaning them off. A cooler plug will show a little more fuel.

 

So should I step back up to stock heat range?

I appreciate the input.

 

Unless you removed these plugs immediately after a WOT run, meaning turning the key off after you release the accelerator, there isn't much to tell about your tune by reading the plugs. Additionally, you need to cut the threads off so you can read it properly.

 

Thats a little much for my purposes. It isn't a race truck. I just want to get rid of my rough idle. I was concerned about the black spots on the porcelain on random plugs. The tune is probably conservative from Magnuson. I would like my Denali mannerisms and a beast when I get on it.