03 F150 4.6l cat problem?
08-21-2011, 12:53 AM
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03 F150 4.6l cat problem?
Ok last week my check engine light came on had the code pulled it was a p0301 misfire in cylinder 1. changed spark plug. ran great til it warmed up than problem came back so i changed coil on plug. ran great til it warmed up again. struggled to maintain 20mph going up hill. i was thinking o2 sensors since pcm operates on default til they reach temp but now it runs like crap cold. i replaced fuel filter checked pcv valve and hoses (yes 90 degree too) checked egr. could this be the catalytic converters even though it seems to run fine in idle?
08-21-2011, 12:56 AM
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oh yeah after the misfire which the COP fixed, i got p0172 and p0174, crazy combination, rich 1 side and lean the other. but after i cleared those codes and ran all my test including a nerve wrecking 20 minute test drive (5 minutes for working vehicles) no codes came back, i've been checking with my own scan tool now.
08-21-2011, 01:27 AM
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That really sounds like a cat problem that it be clogged. When I was unsure if my CAT clogged I unhooked the exhaust manifold from the exhaust it's self. Don't worry if you snap the bolts you'll have to replace them anyway. Run the truck and if you problem goes away I would say that it is your CATS and prepare to spend upwards of 600 bucks at the shop. But if the problem doesn't fix itself then atleast you didn't drop 100 bucks for the shop to tell you that isn't the issue. Just a suggestion
08-21-2011, 01:52 AM
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yeah i try to use OE all the time, and i did check gap. I'm not looking forward to scraping up that much money though. I'll have to try what you said tomorrow. thanks for the help it might take a couple weeks or so but ill try to post an update.
08-22-2011, 02:33 PM
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ok i went to the muffler shop today. he poked some holes and told me my passenger side cats were f'd up and showed me. seems the main cat is about 270 and the upstream cat is specially made for the truck so it would be 349 this is just for the hardware not the labor. what he did is he gutted the upstream and replaced the main and only charged 320. truck runs and sounds better but i'm still babying her for now ya'll know that feeling. by the way yes these cats were on the same side as the misfire.
