I need help, at the end of my rope here. I have a 97 C280 with 175K on it. The problem is it will run great one minute and the next cough and spit terribly. When it is in it's bad mood, it idles fine(700-750 RPM)but when you try to give it the juice it wont go above 1000rpm without spitting and sputtering while black smoke belches out the tail pipe. I ran the codes, the only thing it showed was misfire on different cylinders and it got a MAF fault one time. I replaced the fuel filter and the MAF but no luck.

Not sure where to go next, any help is greatly appreciated.