Hmmm, well I don't think a tune up is going to help. Black soot from the exhaust means the engine is running too "rich". In other words, there is too much fuel entering the cylinders. This can be caused by excessive fuel pressure (bad fuel pressure regulator?), or by a problem in the computer system that is causing the computer to believe the engine needs extra fuel (bad air flow meter, bad temperature sensor, etc). Unfortunately there is no silver bullet for this issue. I'd recommend you take the vehicle to a shop you trust and ask them to test it for you. With such an obvious problem I'd think that a good technician should be able to spot the problem fairly quickly.
I hope this helps,
thank you meyers auto tech.I just recieved my new fluke78 and been fooling around with the coolant sensor and it seems to be bad,I'am also checking sensors associated with black smoke from tail pipe.
thanks for the reply.