My service light lit up the other day, and the code is;

2-3-2 - which according to haynes is 'Idle fuel mix is too lean or too rich.' My first assumption is that it is one of my o2 sensors. I changed the front one a few months back. Could it be the rear one?

Also, I just changed the original exhaust system, I put in a Stara (OEM). The light first started coming on when the old exhaust was hanging off. I have reset the light twice now, but it continues to come back.

Any thoughs?

Look for vacuum leak such as cracked fresh air intake hose, dirty or loose throttle body and/or idle air control.

Is the idle rpm correct and are there any changes in the performance of the car? How long will the car run after resetting the system till the light reappears?

It was a cracked vaccume elbow on the cam belt side of engine. Thanks for the advice.

idle RMP is fine. Car seems to be running better than it has in years, very throttle responsive. I will check for a vac leak. Light comes back on < 100 miles after reset.