Worse mpg followed buy dreaded p0430 code

I have noticed that my last 2 fill ups my mpg have gotten considerably worse, about 230 m.p.t. Today I noticed a slightly rough idle and after driving a few miles my check engine light came on. No loss of power or anything, still runs normal. Drove home and put it on the scanner and pulled up the p0430 code and have been researching it for hours. I plan on replacing the downstream o2 sensors and pcv valve. I just completed a tune up a of plugs, maf, and t.b cleaning. Also changed water pump, radiator, thermostat, fan clutch, and coolant at 100k. Truck not sits at 104k. Any help would be much appreciated as I don' want to throw parts at it and not solve the problem. Thank you in advance

 

Why did you changed water pump, radiator, thermostat, fan clutch...at 100k? Had any failed or was this for fun?

Quick google says likely catalytic converter

 

Leaking water pump. I just don't see a cat going out a 100k

Edit. I installed headers at 90k and cleaned monitored cats while I was at it. Everything looked good.

 

Without some scan data and an understanding of what sets p0420/430s, throwing parts at it is really your only option for figuring this out..

 

I went through all the live streams and all I found was 1 misfire on #6. I also went through injectors and manually cut fuel to them to test functionality. I guess I'm just hoping it' not the cats. Don' want to fork out the non existent funds for them if they are not the problem.

 

Can you feel the miss while driving? Does the CEL flash?

 

i can only feel it at idle. It's not really a miss it's just a minut rough idle. And no flashing mil. First time it has ever come on was today

 

Other than an exhaust leak the only thing that will set a cat code is a bad converter. Be careful though, if there is a misfire (slight, intermittent or otherwise) the raw fuel that goes down the exhaust is what takes out converters. If money is tight, hold off on the cat for now, make sure your plugs and coils are good (no mis-fires at all) and then get a new cat. Also beware of cheap converters. They skimp on the catalyst material to keep costs down and they will set codes again..

 

If you go aftermarket cats, go Magnaflow...2nd best to OEM. I just replaced mine after a P0420 code that wouldn't go away, took care of the code and they were $600 out the door. Toyota cats would've been closer to $2k for both, granted I don't expect the Magnaflows to last nearly as long but you get what you pay for when it comes to cats.

 

Yeah I am aware of cheap cats. Oem or magnaflow. I was unaware that magnaflow made CA compliant cats though

 

P0430 is bank2 which is driver's side. Since your only getting one code, try swapping the sensors side to side and see if the code changes to bank one. If it stays the same, it could be the cat.

 

They do. I just passed smog after getting mine put in

 

Haven't thought about that. Thanks for the reminder.

 

Did you get the federal ones? Their web site said they dont carry CARB legal

 

They were definitely CARB legal...the smog shops here can't put non-CARB ones in per state regulations...our so I was told. At any rate I passed smog for another 2 years so I'm happy lol

 

What year is your truck? There was a recall for the Cats in ALL 2016’s.

 

06

 

Buy Cataclean and follow instructions.

 

Does that stuff really work? Or is just a gimmick? I feel I would be better off using mineral spirits lol.

 

lol I used it on my girlfriends truck and it worked.
I reset the code a few times and it kept coming up. Was going to use Lacquer Thinner, but my girlfriend was sketchy about it. So I bought Cataclean and ran roughish till it was done running threw the tank, but the code never came back. I can't remember if I reset the code or if it went away after the Cataclean by it's self though. I mean $25 vs new cats worth a shot.