I have had my oil changed four weeks ago and the oil light stays on a little longer than normal, why? I did change the oil before the car needed to, since it has the sensor to detect when oil change is needed. Help. Thanks.

 

Reset your sensor.

Turn the ignition on (but don't start the engine)
Press the "TRIP/OIL RESET" button on the instrument panel for at least 12 seconds

 

the magic "oil change sensor" doesn't exist. all the PCM does to recommend oil changes is track hours, RPM's, (and temp? i think?), plug these into the GM formula, and when they reach some predetermined number, "oil change light" on.