Good evening,
I have a 2006 with the 5.v motor. I got it used and it started to run bad. I had all the plugs replaced and three of the coil packs and the truck seemed to run better and then the check engine knight started to come on and gave the code P0430 and said catalyst system efficiency below threshold bank 2. Their times it would say bank one or both so after looking on this sight and trying a couple of home brews i decided it was time to replace the cats so i replaced both.
Since then i have had several more miss fires and once it told me what cyclkder so i replaced another coil pack but i keep getting the above code.
I clear the code and the truck drives fine until the code is thrown and then it drives horrible.
Taking it out of overdrive smooths it out (do not know why) but i do not understand why i keep getting P0430 after putting new cats
What am i missing?
Thanks

 

Did you have the O2 sensors replaced when you got the new cat's?

 

It sounds like we are seeing the same thing, however you are further along in your troubleshooting. I've got an 06 5.4 with 94k.

P0430 is the only code that I have been able to see. (no other code ever)

I too get a severe shudder/misfire under acceleration in OD, and taking OD off makes it go away. (assuming this is a misfire). I have yet to see any other code besides P0430. (no misfire codes)

If I clear the code I experience no shudder/misfire. This only occurs when the P0430 code is present. The P0430 code seems come back after about 50 miles.

I did change plugs hoping that may help, and figured they needed done anyway. Cleared the code at that time, and it again came back after about 50 miles.

Debating/wondering what to do next?? It seems there are suggestions to change COPs, Cat(s)/O2 sensors / injectors. All of these seem logical, but jfp3205 has changed Cats and COPs and is still seeing this problem.

I'm kind of at a loss, because the misfire/shudder only occurs when the catalyst code is present P0430. If there was a bad COP or injector, wouldn't the misfire occur more consistently? Also, I don't understand why I can't pull a misfire code?

Any other ideas, thoughts, suggestions, anyone, Bueller?

jfp3205 - Have you tried anything else?

Thanks in advance! This forum has been awesome for me since owning this truck.

 

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Did you try to have the drivers side manifold inspected?

 

I do have a leak on the passenger side, but I thought the P0430 was driver's side related.

 

following

 

yep,
You are right about the drivers side. I apologize for any confusion. I will go back and edit that post.

Q:
Which cylinder did it show?
Did you replace the o2 sensors on the drivers side?