2003 Ford Focus bad EGR Valve?

This is pretty common problem with the 2.0L motor, this is definately a vacuum leak, check the PCV elbow below the throttle body (the rubber usually will split) causing a huge vacuum leak! As for the oil light I would suspect a faulty oil pressure switch, but also with the vacuum leak the idle could be dropping low enough to cause the switch to close! Repair the vacuum leak and retest. ADDED: There is no PCV code but, if it has a vacuum leak it will set a P0171 (system lean bank#1) Also the EGR valves rarely fail on the 2.0L the DPFE (differential pressure feedback egr) sensor is usually the problem!