anyne have experience with the cheap magnaflow universal cat? My local auto parts store has one for $80 and describes it as a pre OBD2...although it says for 97-99. Its the cheaper of the 3. Theres a mid grade and then a OEM grade. I was told no less than mid grade or i might get o2 codes.

 

No less than OEM grade is probably going to throw a code. These cars are picky.

 

Have you ever herd of a trick involving spark plug de foulers?

 

Yeah. You space it out. I just went with a tune though lol

 

I've read a lot of people with non-oem cats on multiple makes/models having success eliminating the P0420 code with the spark plug non-fouler.

If you want the PCM re-programmed, check the link below:
https://montecarloforum.com/forum/pr...impalas-42773/