Ash on Plug#5

[JimmyB]

I have a 98 Tahoe 350 cu in. A month ago I was getting loss of power and hesitation. Eventually I got a check engine alert. The scanner told me it was a misfire for cylinder #5. Cylinder 5 was covered in heavy ash. I replaced the plugs and wires and power has been restored. After 250 miles I noticed that the ash is developing again on the electrode side of the white insulator on plug #5. I checked the #1 and #3 plug, as well. The othe plugs were so clean you could eat off them. Any ideas? Is this indicative of a mechanical problem i.e. head or electrical?

 

[SunlitComet]

you are either burning oil or coolant. oil thru a worn valve guide or seal. coolant thru a broken head gasket. notice any loss of any fluid?

 

[JimmyB]

I have a small leak in my intake manifold gasket of coolant from the front ATV sealer.
The gasket was replaced 2 years ago with a felpro.

 

[SunlitComet]

well if it is leaking from the rtv sealer something is wrong with the install.