Hand wrench, but I saw him do it and it was tight Tomorrow I will check it But there did not look like any exhaust leak anywhere. No smell or sound And that would not cause the engine to sound rough, would it? Open headers dont

 

After reaching 45 miles with no codes, I just got a PO420 code. My cat is new, although not the CARB one I was reading that oxygen sensors could also trigger the code, and that they only last a maximum of 100,000 miles Is this true? I have over 120,000.on mine

 

I don't know about 100,000 miles mine was still good at 300,000.
If the cat is brand new, they can throw P0420 until they burn off a bit, usually 100-200 miles.

 

Depends on the sensors , but they can deteriorate quickly from any coolant or oil burnt off

 

If you don't want to hassle with a P0420 code you will want to use OEM O2 sensors.

 

Funny you should say that Immediately after installing the new cat, I threw the 420 code But then it stopped.....until last night
And so close to the 50 mile mark.when I can get it inspected.

I have to go on the highway so we'll see

 

By the way my 2006 only has 1 oxygen sensor. I thought you needed to have 2, on each side of the catalytic converter

 

There has to be 2. The #1 may be on the exhaust header instead of the pipe, #2 is after the cat.
#2 is the one that throws P0420. #1 controls the A/F.

 

my bad. It is on exhaust manifolmanifold. There was a bung on the new exhaust pipe with the flex and cat that I plugged. Is that a better location? If/when I replace them should I move it there?

 

I would leave as is. I don't know if the computer is programmed differently or not. Probably would work but I like to be safe.
Be sure the bung has the sealing compound on it.