ka24de-t problem. after 3k rpm 10afr

i need help my car dont work.

when i rev past 3k rpm my car afr jumps from 13s to 10 flat. if i keep accelerating higher rpm ull see black smoke out my exhaust. my car ran fine for past 2years without this issue. its like no boost is built and struggling to accelerate past 3rpm.

just a background info. i replaced the maf sensor with other ka mafs and it still the same. i have a chipped ecu jwt and installed with a safc2 to play with the afr to correct it.

i have no idea where to start to narrow down the problem to fix. my mafs plug and wiring look fine and shiny connectors.

please give me some insight. much help appreciated.

Running veryyy rich on boOst man! how’s the spark plugs?

you said its like there is no boost being built, do you have a boost gauge? maybe you have a boost leak somewhere causing your car to run lean when you start building boost