Half, did you change the O2 sensors when you installed it? New Cat should have new sensors to go with it.

 

Yes,shortly after I put the new cat on I did but,didn't need it.

 

I replaced my bad rattlin cat last month ($218.00 universal hi-flow welded in at thrifty muffler and brake w/ 1 year warranty) and within the week... check engine light... the O2 went next got it from CarQuest it was a Bosch with the correct plug.. Everything running good much better performance and sound...