[KevinH1990]

When driving home on Tuesday my check engine light came on. I made one stop on the way home and then I didn't drive the car (2000 non-S, 5 speed, 39,500 miles) again until tonight. I drove it to AutoZone and the they pulled the P1117 code - P1117 Oxygen Sensor Heating 1 After Catalytic Converter - Below Lower Limit.

When I left AutoZone, the CEL was off. I don't know whether the person who helped me reset the code or it went off on its own. Here are my questions:

1. Is it OK to drive the car? I have a 30-mile commute to work. I expect the CEL to return, but it will be difficult to bring the car to a technician for the next few weeks due to job demands.
2. I replaced the MAF sensor last year. Should I bite the bullet and replace all four O2 sensors or just replace them as they go?
3. Is this an easy DIY job or should I leave it to a technician?

Thanks or your help.