Had left side Cat fail.. Im thinking its wise to do them both together anyone done one and lived to regret it, or am I being to nervous?

oh 2005 F150 Lariat Screw 4x4 180k had motor done at 160 something K

 

My passenger side grenaded itself during a road trip. I just had a universal welded in. I attribute it to a factory defect. 210 bucks and 12k miles later, no issues at all. I did not replace both sides.

 

HEH the dealer told me I was lucky Ford doesn't make theirs any longer around 2000 for the part.. he told me after market was 500 I said I dont think so I already was googling it and found them for 200 is.. 250 with shipping from Rock Auto for a walker one..

sigh

 

Those are the bolt in pipes with cat. Any muffler shop will be able to cut the old one out and replace with a universal...unless you are in a **** state where DoT do visual inspections for CA compliant cats, a universal will do the same thing.

 

Do our trucks have 2 or 4 cats?

This thread is saying some have a cat behind the O2 sensor.

IMO the emission tampering law is probably not an issue, i'm with post number 19
https://www.ford-trucks.com/forums/8...ng-cats-2.html

 

I know '04 has 2 cats, at some point in time it went to a single cat per side.

I replaced both sides on my brother in laws '04 (both were bad) with Bosal brand from Rock Auto. The passanger side did not seal correctly and I had to order a replacement.
Bought them from Rock Auto.

 

I installed both sides with the walkers from Rock auto. Was'nt too bad of a job and no issues as of yet and its been over 2 yrs. I did from manifolds back

 

When the cat goes bad do you get more than a check engine light?

 

I think the upper ones are a "pre cat" then you have the normal cats where the downstream o2 connects. Typically when we refer to cats, we are talking about the lower ones that are visible. When you have a failure, you can get a p0420 or p0430, depending on the side. You also get sluggish acceleration, in my case misfiring above 50% throttle, backfire, and a difference in sound. If you have a OBDII tool, you can watch the lower o2 sensors voltage. They should be about the same, pulsing. A bad cat will alter the wavelength.