2000 Buick Regal

Engine Mechanical problem
2000 Buick Regal 6 cyl Front Wheel Drive Automatic 101000 miles

While driving, car shut off. While trying to restart, it would usually stop again in 0 -3 secs. If it stayed running, the RPM's go up and down, and get black smoke from the exhaust. After sitting for 5 mins, it ran fine. No check engine light or codes yet. From reading other posts, I am planning on checking/doing a general tune up, w/ plugs/wires, fuel/air filter. Any other suggestions?
September 19, 2009.

Try cleaning out the idle air control valve, check the throttle position sensor and MAP sensor, also clean out the EGR valve-

Black smoke points to rich mixture: Possible causes include a bad O2 sensor, excessive fuel pressure (bad fuel pressure regulator or plugged return line), leaky fuel injectors, dirty air filter or restricted air inlet, or a defective coolant sensor that prevents the engine management system from going into closed loop mode.

Sep 19, 2009.