Check engine light on 1994 Oldsmobile Silhouette

My check engine light comes on/off. The vehicle is at 150XXX miles but the engine is not (new engine). Vehicle is slugish at times and needs a tune up but this would not call for the engine light coming on. Is this a preset command in the computer? How is this reset.

Asked by for the 1994 Oldsmobile Silhouette
Sounds like a failing oxygen sensor, sometimes weak oxygen sensors will make the check engine light go on and off.
Also might try cleaning or replacing the Mass Air Flow Sensor