Why is my jeep low in power?

I have a 2002 Nissan Patrol Jeep. Everytime i'm driving it and you give it more throttle it won't take it, and it starts to put black smoke and is also low in power. Is this a filter?, I installed a new air flow meter but that didn't work, could it be something at the pump, or a throttle sensor or some other sensor PLEASE HELP :(