|
High CO is rich mix/incomplete combustion and you're not TOO far off. The spark plug does look a little rich to me.
If you're running the stock fuel rail and everything else stock, the fuel pressure regulator may not be able to bleed off quite enough pressure at low rpm/idle from the big fuel pump.
You might also use a lower heat range plug with a hotter spark at idle/cruise (the tradeoff being more risk of detonation, but they're not doing a WOT run for the emissions test, right?). BKR5E-11 is super common even in some turbo OEM applications like the VG30DETT, I know the 6 heat range is what the CA used stock though.
|