V6 spark plugs.
 

Changed the spark plugs on my 2010 4.3 liter V6 WT at 105,000. The plugs from the right bank of cylinders showed only a little wear. The plugs from the left bank, the ground strap below the center electrode on each plug was very badly worn.
Seems like the plugs should not have that much variation from one bank to the next.The engine seemed to run okay. Checked to see if any codes were set and there weren't any. Engine runs fine with the new plugs. Any ideas??

Talked to a mechanic; he thought that probably it was an oxygen sensor issue. But since no codes were set, it is a minor issue not needing any repair. The monitoring equipment is very sensitive and if the sensors were reading out of spec. a code would have been set.