I changed my spark plugs the other day and all of them were spotless besides the last one on the passenger side. It seems to have a kind of sludge on it that at the time smelled of gas. I changed the plugs about 6 months before this so it hasnt taken long to get this bad. After I saw this plug I ran some Techron fuel treatment in it and I fouled an o2 sensor on that side... I think thats a good sign but what does this look like to you.
What are your thoughts?