Whats going on with these plugs?

[davidn]

Recently changed leads and coil packs after hesitation and misfire. All seemed fine until today, accelerating in 2nd starts kangarooing, mil light flashing intermitantly and generally feeling flat but seems to clear only to return a little later.
Ran the software - no faults reported but crazy adaptives. Pulled the plugs - even bank all looked the same and seem fine to me. Odd bank 1 & 3 have heavy carbon deposits, 5 & 7 better but still some deposits.Plugs were all changed about 2000 miles ago.

Plug 1

Plug 2
What's causing this carbon build up?
Cheers
David

[GreenV8S]

Dunno. Carbon typically means it is running rich, but what you've got there looks very light and might just be a sign that the plugs haven't been getting hot enough to clean themselves.

[davidn]

That was quick, thanks Peter. I see, so it might have been caused by the duff coil pack, the odd bank pack was split and generally knackered so I'm guessing plugs 1 & 3 hadn't been firing too well and this is what you say may have caused the build up.
Okay, I'm going to change them and and keep an eye on them.
Thanks
David