I am having a problem with my 2000 Integra GSR idling after rebuilding it. It was bored out 40 over, oversize rings and pistons and type r cam kit w/ springs. When I got it back my mechanic told me that it wasn't idling right, too high or too low and the check engine light was on. The code was reading Oxygen Sensor so I replaced it, light went off for a while now it is back on reading the same. Some have told me that I need to have ecu remapped. What are my options? Can anyone help? Thanks,

 

Which O2 Sensor is giving you problems? Bank 1, or 2? (Pre-Cat, or After Cat)

Did you set ignition timing correct?

Check for Vac leaks?

You should have the car tuned after the above issues are worked out.