TwoC400s

I've been having some long start and initial rough idle issues for a couple of months now, so I decided to pull the driver side spark plugs and see if anything was immediately noticeable.
The middle cylinder on the driver's side is just BLACK.
Thoughts?
I'm running Shell 93 octane on map 2 of the JB4.

I have in the past run octane booster and map 3, but that was for less than 3 weeks total.

MaverickC43

I’m sure you’ll get a lot of people saying
“send the logs to bms”

TwoC400s

Yeah, I sent them my initial logs, and they were not very helpful.

MatthewJ

I have heard of injectors failing on several C43/C63s with higher mileage. Wonder if two of yours are leaking.
Also i assume you have the green fuel plug in on your JB4 and with the log have trims in a normal range?

TwoC400s

Yes, green plug is in.

I've set it to map 0 for now. I changed the spark plugs and am still getting occasional long start and rough idle.

I put a couple of bottles of fuel system cleaner in the tank and am going to change that cylinder's ignition coil.

I may try a GDI valve cleaner like the STP -pro-line and see if that does anything.

MatthewJ

I like the amsoil DI cleaner. Has a bunch of PEA in it for carbon but I have to admit I don't ever notice a difference after running a bottle.

TwoC400s

The gumout with regane is a very high level of PEA as well.

The STP Pro-line is directly injected into the throttle body with the engine running.