If you do not have the equipment to do so, switching them will rule out a bad sensor.

 

Thats true if it only flags one code, then switch them and see if the code changes.

 

My buddy has a voltmeter to test the O2 sensors so I'm going over there tomorrow to test them. We may switch them around too, we'll see. I hope it's the sensor, much cheaper as opposed to a new cat.

 

Before testing the O2 sensors or cats I decided that we were going to disconnect the negative cable on the battery for about a minute and then reconnect it and see if the error code comes back. I've driven just a little over 20 miles since and the light is currently off. So I'm wondering if it was just a small mixture of a bad batch of gas thrown in there and it triggered it. Who knows. It's off now, driving like normal, so I'm happy. Thanks for all the advice guys! I knew I came to the right place for help.

 

If you've only driven 20 miles I doubt seriously that the "drive cycle" requirements for self testing has taken place. Give it to 50+ miles and then if it's still off you can take a guarded breath.

 

Oh yeah I know I'm going to be watchin' it closely but it's still nice to see it not on.

 

The "enable criteria" for the diagnostic test to run may not have been met yet, and it may require 2 consecutive failures to illuminate the MIL. Keep drivin!

 

Yes. The P0420 requires two errors to set off the CEL. I can confirm this, as I have a ODB2 Code reader. Whenever my CEL comes on, it's two seperate P0420 codes. I'm in the same ballpark as all of you. I'm not messing with it until it starts affecting engine performance or falling apart.

 

That's a really poor plan these days. If the CEL is on all the time it won't be able to tell you when you have a real problem. One of my customers had his light on for years for an EVAP leak. He brought it in when it started running bad to find that he had all but destroyed his engine. If he had spent the money to fix the EVAP leak it probably would have saved him a ton of money down the road.

 

As I said, I have an ODB2 Handheld computer, I just keep it in the truck and nuke the code 0420 code whenever it comes on.

 

So far I've gone about 70 miles and no light on. I'll have to fill up or atleast put some gas in my truck tomorrow or I won't be going anywhere so I'll go to my normal fill up station. But so far everything looks promising.

 

I have an 02 F150 with the same code. Could this affect shifting in anyway?

 

Alright, 155+ miles and no error code. I'm thinking whatever it is has passed (i hope). Thanks again for all the info guys, much appreciated. I knew I could get help here.

 

i have a 2000 ford f150 with a 4.6l 4x4 i've brought it to the ford dealer 2 times know and the first was cause of my windshield leaking onto my gem and lean on bank 2 brought it there today and know i still have lean on bank 2 so they told me to change plugs on that side ,i did and it still has a rough idle but if i give it about 200 rpm it runs great ford said the o2 sensor was ok but what do you guys think is it a pluged cat.,or o2 sensor i know its not the after cat. sensor but i know the before cat sensor is the one that controls air fuel any help would be a much thanks and if i could a 24 of beer lol

 

Sorry to tell you this chevsucks but it is most likely the cat. I had to replace mine recently when I had this code. Others on this post suggested switching the o2 sensors to see if the code follows. You may try that first but as ranger said 95% of the time it is the cat.