1998 Chevy Truck catalytic converters

This may be due to an engine tune up issue and the O2 is just the symptom and not the cause. Do a general check-up on the engine before assuming the Cat is bad.

[quote:e18beef2d6="dtorres"]Other Category problem
1998 Chevy Truck V8 Four Wheel Drive Automatic 165000 miles
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engin light on OBDII code PO420
THE OXYGEN SENSORS MONITOR THE CATALYTIC
CONVERTERS ABILITY TO STORE OXYGEN. iS THERE AN ADDATIVE TO RESTORE THE CATAILTIC CONVERTER[/quote:e18beef2d6]

What you have is an o2 sensor before and one after the converter
and when reading of those sensors is close to each other
that is indication that the converter not doing its job burning the access fuel left unburned
and you have to replace the converter