acooken

I tried to attach pic but not sure it made it. Its and L59 eng and this is the only plug that has abnormal wear. This plug has less then 7000 miles on it.

73shark

Welcome to the forum.

The center electrode looks extremely burned. It also appears to be oil fouled. For others to help, we need to know year and make vehicle.

acooken

04 tahoe with 105k miles. This is only plug like it. I detected a slight miss in eng. It didn't set a code.the treads of plug did have oil on them. Yeah it looks bad. Also tail pipe has a sooty look to it. On first start of day for first 10 seconds I hear a very slight knock that goes away. Oil pressure is never low or below 40 psi. The knocking or piston slap sound is louder on cold winter days than hot summer days. Truck get typical mpg. 15 city 18 hwy. It is awd.
Anything else.

acooken

I wondered if it was worn valve guide, bad rings on piston, bad plug wire or coil, crank position sensor, Or bad injector. Thought id ask the experts before beginning my guessing game. I changed the plugs 7000 miles ago and this us what the #7 looked like then also. They r original wires n coils.

MDTAHOE

It is burned oil fouled.

acooken

To me it looks like oil cooked down around lower part of electrode and up on the strap and near tip of electrode white. Like a lean burn look. Sorry for lack of proper terminology.

acooken

another symptom is on hard acceleration no smoke out tail pipe till I hit 5k rpm. And when it does, it's black not blue. So could it be a defective injector? Leaky or maybe just dumps fuel @ high rpm? Help it greatly appreciated.