My 1996 buick road master collectors edition has 111,000 miles, It floods and burns the fuel very rich

Change your ECT(electronic coolant temp sensor). fairly inexpensive, and can cause the rich running and black smoking pipe. also check your wire connection going to it. Had a 3.8 camaro with a new sensor, but the connector was not getting good contact. $20 fix. A 96 should support a OBD2 connection, so your local part store could give you a code refrence(Pxxxx) and most of the time be ab.le to get you the part. Look for the sensor around the thermostat housing area. If you have a 3.8 engine, it is a bear to get to, but do-able. You should have 2 wires running from it.

thank you but the ect was the other sensor that was replaced. the mechanic replaced the wires as well. when we took the plugs out all the ones on the driver side were clean, but the ones on the passenger side were all 4 covered in black smut

Is there ant other suggestions?

Ever figure it out? Have one with 126,000 miles on it, and I've just recently started chasing the cause. Replaced fuel pump yesterday. Please tell me you figured it out