Hey all, I recently got my 98 V40 T4 back from the volvo "specialist" in Brisbane and then took it to my regular mechanic who informed me that the car had the wrong plugs in it. The specialists also sold me a new set of the same plugs because the car was misfiring and chewing the fuel.
I finally got round to changing the plugs (bought a set of volvo genuine plugs from the uk) which was pretty straight forward but I am struggling to make sense of the condition of the plugs that I took out.

There is a sooty black coating on 2 of the 4 electrodes on 2 of the plugs and under the black coating is a baked on white deposit.
If anyone has any insight into spark plug reading it would be much appreciated.