P0420 Code Problem

[Fordman999]

So recently I got a check engine light and when I plugged in the diagnostic machine it's reading P0420. I did some research and see it is either bad oxygen sensors or a bad catalytic converter. My question is that coincidentally this code came up after I started using Amsoil oil and I think it is not burning it effeciently and something is going on with the combustion with that oil. Also since Amsoil made the claim you don't have to change your oil for 15,000 miles, I haven't changed it in about 8,000 so far, but again what makes me think it is related is that I never had this problem until I began using that Amsoil. Does anyone have any idea what the problem is????

2003 Ford Explorer XLT

 

[Number4]

It's just a coincident. And I'd not run oil past 7k miles without testing it. At which point it's just easier to change it.

What are the values for your short and long term fuel trims?

 

[Fordman999]

It's just a coincident. And I'd not run oil past 7k miles without testing it. At which point it's just easier to change it.

What are the values for your short and long term fuel trims?

Hey Number4 I don't know what you mean by fuel trims, I used a code reader from a friend of mine, it was an inexpensive code reader. Is there a particular code reader I should use? When it comes to codes I rarely have gotten any in the years I've had my explorer.

 

[Number4]

Even a basic reader should display them.
There's bank 1 & 2 (drivers / passengers) short term and long term.
What you are really interested in are the long term values.
srtft1 srtft2
lngft1 lngft2

Also, see what the voltage is for the O2 sensors.
On the O2 sensors you should get values that fluctuate, note the lowest and highest value and post them here.

Here's an example of how it may read on the scan tool.

 

[Fordman999]

Even a basic reader should display them.
There's bank 1 & 2 (drivers / passengers) short term and long term.
What you are really interested in are the long term values.
srtft1 srtft2
lngft1 lngft2

Also, see what the voltage is for the O2 sensors.
On the O2 sensors you should get values that fluctuate, note the lowest and highest value and post them here.

Here's an example of how it may read on the scan tool.

Thanks!