Advice: Replace 1 or both CATS

[theblackesteyes]

Hi All,

I need to replace the drivers side CAT on my '02 T/A. My plan was to purchase a Magnaflow Direct Fit Cat p/n 23477. A couple questions: Has anyone used these CATS and have you experienced any issues? Also, will replacing just the driver's side cause any kind of issues with the computer? Both CATS are OEM so I'm wondering if I should just do both to avoid any potential issues. Thanks for the help!

[SMWS6TA]

Best advice would be to go ahead and replace both if you can afford it. If in a pinch then you can do one and come back later.


I can't say from personal experience of the cat (got LT headers deleted CATS)

[chuckstop00]

I replaced my driver side cat last july or so, got a magnaflow from advanced auto parts, seems
to be fine sofa! Hardest part is getting the old one off. I just bit the bullet and broke the studs
off the exhaust manifold, then drilled them out and replaced with through bolts/nuts. BTW, my
'00 Formula hit 294,000 the other day.

[SteveC]

I would replace both, however with the stock units, why?, if your state requires "smog certification" and you have to go through a "visual inspection" before the dyno test, you will fail with aftermarket cats .

Here in California they will accept converters with CARB numbers (not applicable in your state), however good luck in finding those.

[pajeff02]

I have one GM replacement cat remaining that has maybe 20,000 miles on it. Can't remember if it is the driver or passenger side without looking. I shipped the other one to a member in Arizona last year. Let me know if you are interested and I'll go take a look.

[SMWS6TA]

I have a quesion on this subject:


Our cars are getting up there in their age. Mine has hit her sweet 16, my they grow up fast.

So..I can't foresee GM building CATS for a lifetime of our vehicles. So at what point does a state say F' it and CATS are no longer required to be "factory replacement"?


This is just for future reference when I may one day move to a restrictive state that has these inspections....

[cammed goat]

I don't think there are any states that wouldn't require cats.

[pajeff02]

But there are some that are a lot less strict about enforcement.