Engine Performance problem
1994 Buick Century 6 cyl Front Wheel Drive Automatic 176000 miles
----------------------------------------------------------------
Starts OK, but idles rough and stumbles on acceleration when cold.This condition improves somewhat with warm engine, but still idles rough. Has good power on acceleration when warm. Have replaced spark plugs. What else should be done to improve performance?

check vacuum hoses, idle air control valve and mapp sensor.