I have recently picked up a 2005 F350 with the 5.4, which has 212k on it. Has a check engine light on for P0420 and P0430, as well as some kind of a 'ignition coil 'D'', I forgot which code it was as I deleted them at first to see which would come back. After driving it, the P0420 and the P0430 came back, but not the other, yet probably.

I'm guessing the misfire due to the ignition coil caused the cats to go bad and the 420/430 codes, unless these codes are coincidental and the cats went due to high mileage.
Either way, I'm pretty sure I will need to replace the cats and was wondering what the cheapest route is for any of you that have had this problem. Should I get individual cats and have a shop weld them on? Should I go to Advance Auto parts or Auto Zone and get the whole pipe with the cats attached to them already for like $700 and then get them installed? I anything will involve welding, I would have to bring it in to a shop.

Also, in regards to the ignition coil misfire, what a good way to check which one it is? Any more info is greatly appreciated too.

Thanks in advance.

 

Not 100% sure about all of this but my check engine light was on when I bought my 06 triton V10. I had a friend with the AutoEnginuity scanner check it. It came up with a PO420 code but also showed Catalytic inefficiency. In my case the cat isn't bad just not operating at 100% efficiency. Not wanting to lay out money for a cat system I checked the net. Gumout makes a product called Cataclean that cleans the cats. It got pretty good reviews. The stuff runs about $25.00 a bottle. I haven't tried it myself yet. They want the gas tank at 4 gallons when you use this stuff. I don't drive my truck much and when it gets to about 4 gallons I'm out of town pulling my travel trailer.
From what I read on the reviews the best way to use this stuff is get the vehicle to operating temperature - take it out on the open road and FLOOR it for a bit. Let off the throttle and let it cruise down for a bit then FLOOR it again for a bit. Go to amazon.com and check out all the reviews, you'll see what I mean. Even if I have to do it 2 or 3 times like a couple of people did $75.00 total sure beats the hell out of spending $1,400.00 on a California Cat system for my truck.

 

Thanks for the info. I haven't heard of it, but it sounds like it may be worth a shot. I'm a bit skeptical with how my luck usually runs, but I'll definitely look into it and keep my fingers crossed.

 

Auto Zone carries it too if you have one near you. Same price as Amazon $25.00 a bottle. Before I buy stuff like that (it seems to good to be true) I check out Amazon because they have reviews for everything. After clearing the PO420 code on my truck it takes about 60 - 75 miles before the check engine light comes on again.

 

Yes, mine does too.

I picked up the Cataclean, along with some MAF sensor cleaner and Lucas upper cylinder lube/cleaner. Hopefully this combo will help - we'll see.