New to the site, glad to be here to hopefully gain some knowledge.
Just bought a 2005 Ford F-150 from a military friend for way under blue book and was warned that the check engine light was on. Had it checked out and it was reading some sort of bank 2 code. The guy said it could be an O2 sensor or could be a failing cat because they are notorious for going out after 100k. Does this sound right thus far?
Right now I am trying to figure out what to do.
I wanted to install a new exhaust system in the near future. Should I replace the cat on the left side completely or start with the O2 sensor? I would appreciate if someone could explain to me how the CC works with the exhaust and what my options are with regards to being economical.

*He priced the upstream O2 sensor at around $80 and the CC $400 and some change.

 

Please post the exact numeric code for proper diagnosis.

 

P0430 Catalyst system efficiency below threshold (bank 2)

 

That's not an O2 sensor, it's a failing cat on the driver's side.

The cheapest/best way to take care of this is replace all the cats with 2 universal high flow cats, one on each side. It would not hurt to replace all 4 O2's as long as you are redoing the whole exhaust. Each side has 2 O2's - one before the cat and one after.

 

^ x2 that. Replace the proper aged parts with fresh new ones. The hi-flow cat method is the most popular and when done correctly very efficient in cost and sound. If a part has an opposite component, always replace items in pairs. It is only a matter of time until it's relative twin will be near failure. You can gain a good amount of money back for the original catalytic converters by scrapping them.

Another thing to note, have the truck tested for a rich or lean condition. The 2005 models had an injector issue which lead to the premature death of a lot of 2005 engines and catalytic converters. A bad cat is a good sign of this issue.

 

Thank y'all both I appreciate the feedback! Learning as we go...

So I was looking at the Magnaflow Cats online to purchase. As far as the price goes, the total is about $740 for both. Does that sound right? Or is it not necessary to spend that much and go for less expensive cats like Eastern or Walker. Here's the link:


When they say "direct fit" does that mean no welding is necessary?

Thanks for the feedback and I appreciate you bearing with me!

 

Those direct fit pieces cost a fortune. If your original downpipes are in good shape I would have your factory cats replaced with #94106 Magnaflow cats, properly welded into the downpipes out of the truck for a leak-free weld job.

 

BTT, looking at this thread, I have the same truck, same problem, same code. Wondering if I should bother replacing just the sensor first?

Is cat replacement easy? I'm a shadetree mechanic with a good welder.

 

P0430 is *NOT* indicative of a bad sensor. You have a bad cat.