Chevrolet Repair: Catalytic Converter issue, 2000 chevy cavalier, spark plug wire

Question
Hello...
I own a 2000 Chevy Cavalier with only 57K miles on it. Recently I had a plug wire fall off, which triggered the "check Engine" light to come on. Since I fixed the problem, the light went off, then came back on even though the car is running fine. I brought it to a friend who owns a mechanic shop. He ran a diagnostic which said that cylinder three was misfiring (of course because the wire fell off). He then reset the chip so the check engine light went off. One week later it comes on again so I bring it in to him again. Now the code comes up as "Catalyst insufficient...under threshold" or something to that affect....it's telling me I need a new catallytic converter! The car runs fine, smells fine, and has no noticeable loss of power...plus it's not that old. Why does this code keep coming up? When should I be concerned?

Thanks,
Neal

Answer
QUESTION: HOW did you FIX the spark plug wire ?. Hopefully you installed a NEW plug wire and did NOT just FIX the old one which is a NO-NO on today's vehicles.


Did you change the engine oil and filter after you fixed the plug wire ?. Because since the cylinder was not firing, Fuel was still being emitted into the cylinder thus dilluting the engine oil.

There is also a possibility that one of the oxygen sensors is reading to high of a fuel mixture due to the oil dillution.

Put a NEW plug wire and spark plug on the vehicle.

Change the oil and filter.

Drive the vehicle and the oxygen sensor(s) may clean itself as it is most likely carboned up due to the spark plug wire.

I seriously doubt that you have any internal converter problem.

You might have to clear the CODE several times until the system cleans up.