Pontiac Repair: engine codes, o2 sensor, scan tool

Question
I have a 2000 Sunfire with a 2.2l, sometimes runs very rough, usually brought on by turning on the lights.  The engine & service light are on.  The codes are 141 & 300.  Any help would be much appriciated.
Thanks Jamie

Answer
Hey Jamie:

Those codes are for a ramdom misfire (300) and a bad O2 sensor (141) both are common on this car. For the 300 code I would suspect a bad plug wire(s) or a lean injector "dirty" the 141 is just a bad sensor code but you would need a scan tool to actually verify that issue as to what the failure is either the hearter is bad or the sesnor is dead. A scan tool would alos show you what cylinder is the most liekly cause for the misfire. That engine uses 2 coils to fire the 4 cylinders if you had 1 bad plug wire it will affect 2 cylinders. It's a place to start. Good luck :}