The #7 hole has a helicoil in it. A compression test showed it at 40% and the plug had a whitish brown color and looked burned up. After replacing the plug, the test now has it at 12% down.. Could the previous helicoil repair have damaged that hole? I was told the insert was allowing the plug to get hot. Or maybe it's not a helicoil but a cheapey repair type that uses a hotter plug? It was a auto lite that was pulled out.

Would a proper time / big Sert fix it? And what can I do to bring the compression back on it?

Thanks!

2000 X 6.8 V10 Limited