03 impala catalytic converter

I have 03 impala 3.8 that has a bad converter I would like any body who has replaced there coverter with a after market converter tell me if thay had any problems with the converter and which brand did you use thank you

See if this may be covered by the extension on cats that GM has been doing, check with a dealer. The std warranty is 7/70 or 8/80 depending on what state.

it has over 127 thousand

The most common issue with after market cats is the P0420 code. PCM has a very tight tollerance for the values coming from the rear o2 sensor. Cat will work fine, PCM will throw a CELL for Cat. Inefficiency. Not everyone gets it though, and some get it very often.

Had probum on my S 10 got some leaded gas and i melted the cat it was 18 cents cheper i will know beter next time so it could happen to any car !

I have replaced mine with a direct fit magnaflow got it from advanced auto parts andt got both o2 sensors and the new gaskets also. all of this was about the same as the stock but more hp and torque and better sound < If you finish off your exhaust with a magna flow resinator and flow master super 44 muffler all the sam price or less than stock, now you will need a new pipe from the resinator to the muffler and someone to mig or better yet tig weld it together and mount it, but the cat I did myself with only hand tools, and the computer will reset the rpm's and gear ratio on its own . it took two hours with putting it up on jackstands and all.

I replaced the cat in my car with an aftermarket after it was plugged and it throws the code p0420. I have a 2003 impala 3.8l impala. I am not sure what brand it was, it was a muffler shop that installed it.

and the computer will reset the rpm's and gear ratio on its own. Please explain that? :confused:

I replaced the cat in my car with an aftermarket after it was plugged and it throws the code p0420. I have a 2003 impala 3.8l impala. I am not sure what brand it was, it was a muffler shop that installed it.

Running rich (what probably plugged the first converter) can damage O2 sensors. May need to replace them, or a bad O2 sensor may have been misdiagnosed as a bad cat.

Please explain that? :confused:



Running rich (what probably plugged the first converter) can damage O2 sensors. May need to replace them, or a bad O2 sensor may have been misdiagnosed as a bad cat.


That is what I thought at first, bad O2 sensors and I replaced both of them. The car was still very sluggish and thats when I was told it was a clogged cat and had it replaced. After that I then need to inspect the car and it wouldnt pass, so I bought another O2 sensor for the rear and it stills throws codes. I also tried a O2 sensor emulator and it took the check engine light off, but it still wouldnt pass inspection. This was about 7months and I soon gave up on clearing the code.