Now i change new plugs and wires.
4 plugs (all 3 radiator side) and 1 from sheet were like new and never used. White and gap was metal colored.
2 plugs from sheet side were like anothers but they have white coating on gap. It disappeared when i sweep it swinger very soft.
I check internet and someone says its okay, someone says it running lean and someone says overheat.
What do you think in this case?
Mpg is not super low and lambda seems to be a new and no faults codes about lean.
I dont know how old plugs was, delco. Outside was ac delco text under rust with every plug.
Edit: electrode and gap were okay on every plug. Ps this picture is not my plug but very similar.