P0421 and P0300

[camo47]

I have a 2005 Jeep Wrangler Rubicon Unlimited with a p0421 code that later threw a p0300 code. I've recently (within the last 20K miles) replaced all o2 sensors. Should I be thinking about new cats? I have 170000 miles on the odometer. Thanks for any insight you may offer.

 

[Chris]

What brand of sensors did you replace them with?

 

[camo47]

What brand of sensors did you replace them with?

NTK.

 

[Chris]

It very well could be your cats, especially with that sort of mileage. My guess would be either the cats or a short in the wiring somewhere.

 

[camo47]

Thanks for the quick response Chris! Do you think damaged wires on the O2 sensors, or some gremlin elsewhere? I may order cats tonight. I saw your recommendations in another thread and I'm thinking this one. https://www.amazon.com/dp/B0031G6YT6/?tag=wranglerorg-20

 

[camo47]

The Cats arrived tonight.
1. Does anyone think I should paint them before putting them on?
2. Should I go ahead and replace the RMS, since I'm there anyway?
3. What are some good recommendations for a new muffler/exhaust. I have a banks on there right now that is probably near the end of its life and I'm 4 linking soon. I'm not impressed by Banks stuff. (I swapped there crack prone header for a stock one) and I'm not looking for loud.

 

[rasband]

1. Does anyone think I should paint them before putting them on?

No, the paint will just burn off and smell while it does it.

 

[camo47]

Checking back in on this thread. I’ve been doing major work to my Jeep and only recently had the chance to drive it with the new cat setup. My precats were blown out and restricting my main cat. The Jeep drives MUCH better and the code cleared themselves