My BMW M3 E46 seems to be running rich on start and getting poor mileage so I pulled the plugs to have a look. I know how to read normal plugs but these are NGK Iridium plugs and I'm not sure how to tell whether these need swapping out. I don't know how many miles are on them.
There are 3 others but they're all about the same. These seem okay to me, but then I've never seen this type before. Should I clean the threads up and re-gap them or replace? If there is a good chart for iridium plugs I'd love a link.