Both the oil burning and the defectiveposition sensor would have hurt the CAT.
A defective camshaft position sensor can cause problems ranging from no sparkconditions including excessively long cranking time when starting cold, rough running, poor , stumbling or hesitation, mileage drop and stalling upon .
However before replacing thewe recommend also looking into perhaps a defective rear . Having leaked oil into the combustion chambers and through the may have contaminated your ‘s oxygen sensor. With a defective (out-of-range, weak, lazy) rear oxygen sensor your Civic’s may think the CAT is damaged when in fact the sensor is not functioning properly.