I have a 1999 SE-L with a 5spd and the Check Engine Light came on the other day. So I check it and the code is 0702. From reading the forum, the code means that there is something wrong with right cat. Does anyone know what might be causing this or how to find out (test) what part is at fault? I hate to replace a prefectly working cat. The car is stock. No mods...yet. It has 100,400 miles too.

 

0702
Diagnostic Trouble Code 0702 points to a problem with the three-way Catalytic Converter.

The Cat is one of the principal components of the emissions control system. The Engine Control Module monitors the signals from the two front Oxygen Sensors and the one rear Oxygen Sensor. The signal frequency of each sensor indicates something about the condition of that sensor. A comparison of the frequency of the front sensors with the rear sensor indicates something about the condition of the Cat.

This malfunction was detected when the ratio of the signal frequency from the right bank front Oxygen Sensor to the signal frequency of the rear Oxygen Sensor exceeded a critical threshold value. This indicates that the Cat does not have enough oxygen storage capacity. The right cylinder bank is also called the rear bank. It is cylinders 1,3,5. Possible causes of this DTC include ...
- Three-way catalyst
- Exhaust tube
- Intake air leaks
- Fuel injectors
- Spark plugs
- Ignition timing

 

how do I find out which part is bad. You listed about six possible causes. How do I narrow it down? The car runs fine (i.e. normally). Gas mileage is still the same, power feels the same.