Originally Posted by RaceFaceXC
more than 35k... but lots of things may effect the life of the cats. i would verify that there are no other problems before messing with the cats @ 35k. Have been using odd-ball gas or messing with the tune or anything?
I ran my CAT's until ~150K miles until I finished upgrading the exhaust and using new HFC's.
My wifes 99 Impreza L (2.2L) has ~110K miles on the OEM CAT.
Emission parts should last 100K + miles, this is a US Federal mandate!