My mini 1.4 petrol has failed on high co and hc but only by a small amount . Last year I gave it a service to pass the emissions but this year it’s not having it.
I have fully serviced it, added a fuel cleaner and used a cleaner through the air intake and to top it off a Terraclean.
There is no sign of leaks anywhere and the exhaust although on 105k miles has no leaks. The Terraclean guy didn’t have a gas analyser so I haven’t had it checked but my obd readings are showing rich. The cat is getting to 750+ degrees and fuel ratio showing 14.6
The car is still recording 51mpg
The terra clean released some performance I had lost over 10 years but I would say the 0-60 is the same as the day I bought it new. The only issue I can say is when driving under load I can hear a kind of pinking noise from the front. It doesn’t appear if I just rev the car at idle, only under load. Any advice? Thanks