keep getting the code P0420 and i am being told that bank 1 is the passenger side cat and i need to replace it. I had to replace the plugs and one coil pack after i got the truck from it running poorly and i have been told that could have caused the cats to go bad. if that is true, I will replace the cats.
My question is i am now reading that a stuck injector might also cause that. The only symptom I hav ethat might be injector related is poor gas milage. The truck runs good but i have only had it for a couple of months so hav eno history.
Is there any way to verify that an injector might be bad or would I just have to replace all 8 to see if it makes a diff.
thanks

 

I am not sure how much detail you want, but since you asked............
here is a pretty good explanation of checking the cat. The explanations are better in the later part of the video.


Since you did not mention any fuel trouble codes, I did not post video showing that, but I can, if you need it.

If you are not clear on this information, it might be better to have a pro check this for you. It is still cheaper and better to "test, don't guess", than to just start throwing expensive parts at a problem.

Post back, if you need more diagnostic information.