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What is a burn mark? There can be normal deposit patterns relative to the intake valve. Note that the ground electrode also shows a dark spot in the same area. Fouled injectors may be part of the problem as well. Suggest Techron Concentrate which should be used routinely a few times a year as part of basic maintenance.
The deposit in the photo does not look like a major issue. The plug does appear to be running too hot and is "too clean". The plug that you are using is the cooler running plug indicated for Aero performance and up.
What is your ratio of highway VS city miles?
The engine should be running rich when on boost and the plugs will get dark from that. Depending on the heat range, the on-boost deposits will burn off when not on boost, more so with highway miles. Your plugs might be indicating that your on-boost AF ratio is not rich enough, suggesting that the fuel pump cannot maintain pressure at high flow rates or injectors are not large enough. The pressure regulator is also playing a major role. Note that on-boost is open-loop and not managed by the O2 sensors. Ideally, you would pull some dyno runs and have the WOT AF measured. You could make a post on the performance BB, explain your performance mods, plugs, octane etc as well as plug appearance and see what others suggest what the plug appearance means and how to proceed.
Plug appearance can vary a lot depending on what type of driving you were doing prior to pulling the plugs.
What octane rating are you using?
Do you ever hear any pinging?
Plug gap widened from what? Larger gaps can increase power a bit by changing the ionization resistance seen by the trionic system. Gapping at the smaller end if the tolerance range and allowing the gap to erode open towards the higher end of the range is a common practice.
If you Google for spark plug deposits, you will find a lot of pictures that are old for cars running leaded gasoline - not applicable.
How many miles and have you ever cleaned the MAF?
posted by 70.129.23...
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