[mlee19841]

just changed it about 3 weeks ago. i have a 02 impala with 107xxx miles 3.4 v6. i changed the cat. converter and now three weeks later the check engine light came back on. with a cat converter code , i used a universal cat. converter for like 70 bucks, could that be the reason it failed so fast already.

 

[04DetroitLS]

prob isnt the cat, prob is O2 sensor# 2 (postcat), or theres an exhaust leak near that o2/cat

 

[mlee19841]

the o2 sensor before the cat and exhaust manafold right at the start of the system. ill switch it out since its cheap fix

 

[kingnutin]

You could do that, but it won't help. He said post cat for a reason. The computer is throwing the code because the downstream O2 is reading off, I don't see how replacing the upstream will help.

 

[mlee19841]

oh got ya the one after the cat then correct

 

[04DetroitLS]

oh got ya the one after the cat then correct

assuming its a cat efficiency code
if you had the dtc# it would help more

 

[kingnutin]

P0420?

 

[04DetroitLS]

P0420?

lol @ 420

 

[kingnutin]

I'm not sure how to respond to that, lol

 

[DennisW]

just changed it about 3 weeks ago. i have a 02 impala with 107xxx miles 3.4 v6. i changed the cat. converter and now three weeks later the check engine light came back on. with a cat converter code , i used a universal cat. converter for like 70 bucks, could that be the reason it failed so fast already.

Thats exactly the reason. You're gonna have to spend a bit more than that to fix the problem correctly. Cheap "universal" cats simply won't keep the GM OBDII system happy.

I replaced the cat in my '04 3.8 with one from Rock Auto, Maremont brand. I don't know if they carry that brand any more but it ran me like $220 and was an exact fit OEM replacement. At that mileage you would be well advised to replace the front and rear O2 sensors as well, since you're already right there. I used the AC Delco brands, figure it was a safe bet. Expect to spend around $80 or so for the O2 sensors.