2004 F-150 2 bad catalytic converters?

Truck has about 72,500 miles, still under warranty for emissions, dealer will replace both at no cost. No complaints here, but I just can't get my brain around how two cats can go bad at 72k for no
reason. None given by the dealer, they didn't say there was an air leak or leaky injectors, no problems found upstream. I'm worried that the new cats will go bad too.
Any thoughts? Thanks, Matt
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sleepdog wrote:

Ford had a problem with bad cats on my Contour. It was a '97 and the cats died around 30 or 40k. The check engine light came on and I took the car back to the dealer. It was a problem with the cats, either the design or materials, IIRC.
You might also have bad O2 sensors or another problem. If you have too much hydrocarbons leaking through, this could cause a problem, too.
You said there was no problem upstream. I would definitely ask if you haven't already. Also, I would definitely take the truck to autozone or someplace else where they read the codes on the OBDII for free. I would also ask the dealer if there are any TSBs on the problem.
jeff
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I took it to the dealer to have it diagnosed, I already read the codes myself with my reader, P0420 and P0430. Ford dealer did their diagnosis and said there were no problems upstream. The technician said sometimes one misfire will do it, but I'm still skeptical.
The only think I can think of is to test my injectors by pulling the rail off and charging the fuel pressure so see if I get any drips on some paper towels.
I'm just not convinced that it wasn't raw fuel that killed my cats.
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sleepdog wrote:

One misfire won't do it.
I would continue searching on the internet and check for TSBs.
Jeff
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No TSBs on fuel injectors or catalytic converters for a 2004 F-150, checked via my alldata account.
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I'm thinking either fuel contamination or oil contamination, I'll have to keep better track of my engine's consumption and pull the fuel rail off to check for leaking injectors.
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