I have a 1998 Ford F150 4x4 8 cyl 4.6 check digit W 125,000 miles. I had not noticed any problems, live in Maryland, had to go thru required emissions testing and they said the check engine light was not working and the bank 1 oxygen sensor behind cat was mal****ioning. I replaced the check engine bulb and the O2 sensor and it ran fine until I got 225 miles on it and then the check engine light came on. I went to Auto Zone and they checked it on the hand held tester and came up with code P0420. I notice the truck seems to be "holding back" some and this code could be catalytic converter replacement time, my local shop says $1200.00, the other O2 sensor is $54.00 on the passenger side. I have straight pipes now from the cat back already invester $700 in exhaust manifold on passenger side 6 months ago, I am just wondering if this code is a definite on the converter or I should try some others things first?

 

This may help understand your code...by the sounds of it see if your cats glow in the dark at night after the truck is fully warmed up. By the sounds of since you say it seems to be "holding back" it sounds like the cats are plugged up, especially with 125 on them.

https://www.f150online.com/forums/sh...ighlight=p0420

 

Thanks for the info I will check that cat further, I did already order just the passenger side cat and pipe from auto zone and I am hoping I can install myself they sia dit is a direct fit but looking under the truck itself looks like some welding was done so I don't know If I can do it or not, I don't have welding tools or experience.

 

Yeah direct fit is just that, the weld will have to be cut, probably with a plasma cutter or torch, and the bolts will be removed or cut (more likely cut) from the manifold, that will drop the old cat assembly out. To reinstall you'll need a bolt kit from napa to attach the cats back up to the manifold unless they come with bolts if you are lucky. Then to reattache you'll need someone to weld it (MIG would be best).