Question: C5 Z06 P0420 HC code

[bob02Z06]

Hey everyone,
I have a 2002 Z06 Corvette. It had a few issues lately; I thought I got them all resolved, but I guess I am having a few more.

I will go over the history of recent resolved problems. (within past month and a half)
-thrown code for driver side rear o2 sensor. (found that all were pretty bad looking, replaced the two rear o2 sensors)
-Car suddenly ran like hell on the road. Had a misfire and MAF sensor code. Also shop I took car to found a busted valve spring. (replaced the MAF sensor, spark plugs, valve springs, and the front two o2 sensors)

Car ran perfect and purred like a tiger after this.

-I was driving today, since Washington has some unusually nice weather right now. In my drive my check engine light came on, however my car was still running perfectly. When I got home I held the 4 button and pressed the 1 button 4 times to get to the check codes menu. It came up with p0420 HC, which is a code I have never seen on the car. I am afraid I have a catalytic converter going bad on the driver's side; because all of those o2 sensors are new, the exhaust is on tight.

Car runs very well, but I do not want to cause any unnecessary damage to it. Should I just get both of the catalytic converters replaced?

PS: I will be getting into contact with my friend this Sunday as well since he has a code scanner that will let us know the cat temps and any other valuable information.

Any input is valued, Thank-you for reading!

 

[gmjunkie]

Before I just changed out the cats,I'd check all the spark plugs and see if I had one on the drivers side look different than the others!

I've seen a head gasket just starting to leak a very small amount of coolant into a cylinder toss this code!

 

[bob02Z06]

Thanks for that piece of advice gmjunkie! I will check make sure there is no head gasket leaks and make sure all my new spark plugs are about the same. If it is so then yay!

Heck I should probably seafoam the car through a vacuum hose. I could only imagine the amount of carbon in there from that bad valve spring.

If non else works. Then I will just get some high flow cats such as flowmaster.

Thank-you for that info gmjunkie!

 

[bob02Z06]

Update

All the new spark plugs look pretty even. There is no coolant leak. So I just went ahead and pulled the trigger and purchased two new catalytic converters at Napa. I am going with OEM replacement. Dang valve springs cost an arm and a leg when they go out!