I changed the valve cover gasket this weekend on my 94 4.9L.

Everything went well, and the top end looked pretty clean, but noticed something troubling on the number six cylinder.



The whole area inside the valve cover baffle above the #6 was lightly caked in carbon. The #6 itself has that darker color.

What am I looking at? Should I run a compression test? Or is it simply a symptom of the PCV valve being over that cylinder?

 

That EGR tube is the hottest thing in the neighborhood too.

What does the plug look like in comparison to the others?

 

That's what I meant instead of PCV.

I'll pull the plugs after work to see. Should note I have no codes and no CEL. Engine runs as good as it always has