Thanks for all the suggestions. I have replaced the intake manifold gasket. The overly rich diagnosis was not sophisticated. The plugs were almost fouled with black gook and the black smoke was pouring out the tailpipe. I have gone around the engine compartment with carb cleaner looking for a vacuum leak. I am going to take off the throttle plate and clean it in the near future. Having gotten stuck once myself, I am going to replace the crankshaft sensor and rack it up to maintainence. thanks again