Serving Miata Owners in the Delaware Valley Region
Bought a new 2018 MX-5 last year. Only has 2500 miles on it and noticed black soot on exhaust tips, indicating rich mixture. Dealer said this is normal, and so did internet bulletin boards, but I don’t believe it.
Has anyone else experienced this and what, if anything, have you done to fix?
Yes, unfortunately, this is totally normal on cars with direct injection engines. Check out this article from Car and Driver: https://www.caranddriver.com/features/a22974104/black-exhaust-pipes-car-direct-injection/
As far as my experience all miatas from day one run a little rich. That's how they get the power and keep the motor safe from leaning out. Only way to fix is have someone that can recalibrate the ecu on a dyno.