So recently I made a thread about a serious rough idle issue and misfires on cylinder 1 and 3
I replaced plugs and COP's and there was no change, codes are gone but rough idle remains, I checked everything from vacuum lines to cleaning the throttle body. Nothing changed until this afternoon, I was driving and heard a rattle noise which I am all to familiar with, my driver side cat has failed and pieces are bouncing around inside of it. I believe this is the issue I've been searching for. My truck has 165,000 hard miles and has seen lots of off roading through out its life so it came to no surprise it was on its way out.

Now onto the real topic. Can I just remove the cat or cats for that matter, I'm already straight piped minus the cats, so technically only a muffler delete. But I would love to just remove them completely, what about the 02 sensors? Or should I pay the big bucks and just replace the cat? Smog and emissions isn't a big concern of mine so let's rule that out. My truck has 2 cats, one on each side. But only the driver side is making noise. Let's hear some opinions.

 

What state are you in? Do you have yearly or every two year e-checks? I am in Ohio and I know that I would not pass an e-check without a cat. That is one of the things they check for here. But I'm assuming since you said smog/emissions is not a concern of yours that it means your state does not check for a cat or even have e-checks at all. If that's the case then get rid of those cats! I know I would have if I didn't live in Ohio. Your O2 sensor would go off though if I'm not mistaken, but who cares!

 

the issue with registration is my truck is registered in Texas and was originally from Florida, but I live in California. Texas doesn't know that I moved and California doesn't know I live here, I have a license in Texas and CA. There is smog checks in California but since my truck was not bought in CA all I have to do is pay a smog fee because it won't pass the smog test because it wasn't designed to. So inspections are a non issue. im More concerned about the performance. The downstream 02 sensors send info to the pcm to correct fuel/air mixture so what happens if they aren't there? Will i run super rich, super lean? The engine will have no idea how the truck is running without them.

 

I don't know anything about cats . Usually if you get caught in another state without changing plates they fine you pretty good . They key it up with drivers licence, car insurance ,and they use those automated lic readers that read 10k plates a day to see if you are at a school or employed there. Calif is one of the tougher places . Once they zone in on you it can get expensive to get it to pass
inspections .
I would talk to a guy who specializes in testing- changing cats , there is some technology to having back pressure to cylinders etc . F150 torqued seems to know a lot about that . Pm him. I know you are looking for a quick fix and to do away with cats and you are not alone . Many places will not touch something like that .
Glad I'm in florida except when a hurr is coming .

 

The states aren't on their game with that as much as you'd think. When I moved from Texas to Ohio I got a speeding ticket in Oklahoma while driving to Ohio that I never paid, which eventually turned into a warrant. To be honest I never planned on paying it until I was told that it would pop up in the system when I would try to get my Ohio license. I then tried to find the ticket, but never did and I couldn't remember what city/county I was in when I got it. I went to the Ohio BMV anyways and gave the lady my Texas drivers license to see what would happen and it transferred over to Ohio with no problems.

 

Just replace the cat well worth it.. or get a high flow

 

I think that's the route I'm going to go with, found replacements for like 200 bucks that are bolt in, I have also heard removing the cats on our trucks make them sound terrible and 200 bucks is probably what an exhaust shop here in California would charge me to remove them and weld in a piece of pipe.

 

It does not matter what state you are in; cats, along with other Federally mandated equipment are FEDERAL required equipment, and supersedes any state law, if or if not one exists in your state.

 

The 2nd O2 sensor is only checking to see if the cats are doing anything. The 1st O2 is the one that is adjusting the air fuel. If inspections aren't an issue, you can delete the cats no issue.