My Corvette smokes a black sooty exhaust about half the time. I've driven it about 3000 miles in last 4 years. What is the problem and how can I repair?

Black smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor. Some of the causes of excess fuel are a carburetor that is out of adjustment, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor. If black smoke is present, check the engine oil to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil.

Well if it is carburated the i would check the choke to see if it is opening when the motor is warming up if it is fuelinjected then i would try some sea foam to see if in checkters are cumed up from siting you can get it at local auto parts store and this work in the gas and it will help stabiliz fuel when car sit fuel gos bad fast .

It is overfueling. Did you notice it using more fuel than usual. Most common reason is a clogged air filter. It's the first thing to try If you change the air filter and it is not fixed get back to me I can let you know where to go from there. If the air filter is not the cause could you let me know is it a petrol engine.

Black exhaust is rich air/fuel mixture -- You could have stale gas or more likely need a carb overhaul. If that is all u drove it in the last 4 years a full engine service would be recommended--oil, filter, grease the chassis and check all fluid levels.