well here i go again no puntuations and no meanings as far as i kmow i thought i was dealing with adults but instead it seems like there always a few morons or i came here for help not to be judge about my spellings or anything else actually i know that somebody will have two more pennys to say but if you cant help me well then go to i will not ill do my search in one of the other forum they dont seem to look you down (ps thanks to the ones that were help full) oh yeah here is your puntuation................... you can close my page believe me i wont loose any sleep ups i forgot something

 

Holey

Right

Well, if WE are Morons, what's that make you ?

Yea buddy,

 

Well back to topic, I currently tracked down this problem, first replaced cats since the code said they were below threshold, didn't fix it, tried changing injectors and didnt fix it. Then changed spark plugs and fixed it, and gained a lot of lost power and mpg.

To 4wheelerbadtrk, it's annoying trying to understand what you mean without any punctuation...

 

So I recently had this code as well as p0430, which is the same code for bank 2. It's a brand new motor, brand new plugs, new global cops, long tubes with resonators. Now, the codes aren't throw with normal driving, but every once in a while, when I come to a stop, the motor shutters, feels like its gonna die so I throw it in N and hit the gas and it revs like normal and goes back to a normal idle. That's when the code is thrown. It's really weird as it doesn't happen all the time, only at low rpms. I was thinking it could possibly be that the o2 sensors are getting confused from the driving and then when I slow down to idle its not adjusting the air fuel for the reading its getting? Any thoughts seeing how most of the components suggested to be replaced have less than 300 miles on them?

 

I'm surprised you don't have PO420/430 all the time, running just resonators.

 

Nope, been driving the truck for about a week now and its only been thrown once, like I said, right as it was stumbling.

 

Well, the monitor has to fail efficiency 3 times (drive cycles) before those DTC's are set. Stumbling has nothing to do with those DTC's.

It should also be noted that faulty HO2S sensors do not produce the DTCs P0420 and P0430. The sensors must all be tested and shown to be reliable before the Catalyst Monitor can be called by the Executive.

You need converters or a custom tune.

 

Yea, custom tune is on its way. Just haven't gotten it yet.

 

I bought my 05 f150 5.4 used and do not know the past history of the maintenace done. It now has 136K on it. seems to run good. Noticed the exhaust pipe is black. Just got a P0420 code. From reading all the prior posts in this thread, it seems that everyone is in agreement that it most likely is the catalytic converter. I want to resolve this without having to spend a lot of cash replacing parts that do not have to be replaced. Any help would be appreciated. Thanks in advance

 

You may have a leaky fuel injector.........

https://www.f150online.com/forums/v8...ram-07m08.html

With 136k on it you are on your own here.

 

My 05 just threw a 420 this morning on the way to work. About a month ago I put $1200 into it due to 3 bad coils causing the pass side converter to plug up completely. I had to cut it out and use a rod to beat the chunks into small enough pieces to get them out and empty the converter. Welded it back in, but of course I wasn't able to get around the top, so it does have a small leak. Been this way for weeks and hundreds of miles, but today is the first code. Is the hollow converter causing the 420? BTW, thanks to this forum when the truck wouldn't start last week, I was able to fix it for $64 and an hours time due to a bad FPDM. Thanks guys.

 

Yes, think about it - if the converter is gutted, it will have low efficiency.......

 

I recommend getting Magnaflow replacement cats.

 

So tell me, can bad misfires on cylinder #8(bad coil) effect Cat P0420 Bank 1? I was told (by dealer) the gas may have damaged my Cat, but my code (P0420 Bank 1) is passenger side - Cylinders 1-4.
Also, just had all plugs and Coil on #8 replaced at dealer...

 

P0420 and P0430 are left and right cats. I've had long tubes with hi-flow cats since the truck was brand new and have always had that issue. I believe it's due to the cats not reaching optimal temps when the sensor thinks it should. JDM sells O2 bungs that extend the O2 sensors out to counteract this BUT it did not work for me so I just had them disable it since we have no emissions checks in CO. if you clear the code it will come back the next day or on a lengthy drive FYI.