Black soot from exhaust
 

I have another concern that mabe someone can help me with? My Benz has over 238k miles and the motor is as quiet as can be but before I sell her I want to try to resolve this issue. when I start the car and hit the accelrator I get heavy black soot that sprays the ground, almost looks like heavy carbon built up but very almost powdery?? My only thought is that the oil is ready to be changed, very black. I have done all of the tune up recently thinking that the plugs and wires were bad but that didn't change anything. I am gonna change the oil with Royal Purple, I've used this oil in other vehicles including my bike and have found results unlike any other synthetic that I've used before. Could my oil be soo polluted that the contaminates are being sucked up through the breather tube in the right valve cover into the air breather and back thru the engine????? Very confused, I've never run across this before, can anyone help??
Thanx in advance :D

Based on your post, you might have a diesel, ... in which case it would be normal if an older model.

It helps a great deal to post the year and model car you're discussing.

Sounded like a diesel at first......;)

<<<I have done all of the tune up recently thinking that the plugs and wires were bad but that didn't change anything.>>>

Mmmm, so now we would like to know if it's carburated, distributor, ... we're getting closer! Check for a stuck choke.

soot
 

No she's definately injected. I just recently replaced the old oil w/ royal purple and that looks like it might help. I've only run the engine for about an hour but it seems to be clearing up a bit, plus just did a full tune up which was a definate must. I still have a slight miss at idle but I thnk the valves are just a little gummed up, that should hopefully go away once I get the inspection done next week and I can put a few miles on her.