Black smoke

When I start my car sometimes it turns on and then just switches off on its own so I start it and give it gas then I let it idle and it starts cutting out as if it's about to switch off then it spits some black liquid out the exhaust and starts idling properly after a while, when I accelerate it sometimes still shoots out that black liquid, the idles rise and drop as if the fuel is either not being burnt properly or not being pumped properly, while driving I hardly have my foot on the accelerator and as soon as boost kicks in it starts to jerk and shoot out black smoke through the exhaust but if I put the peddle all the way down it will stop but there will be not much power and it is no longer fuel efficient as it was before this problem occurred. Last night I was driving up a hill and the traction control light and EPC light came on and there was no acceleration anymore, I turned the car off and switched it on and the lights were off, it keeps bringing up the service warning but I haven't even done 10000km yet until it's next service, please help me.