[Clydesvx]

I did not need my cats replaced until after 200,000 miles. I did have a problem this time but my subaru tech put something in the intake manifold and let it sit overnight. In the morning they cranked it up and it blew a lot of smoke for a long while. The next day I took it to the test center and got better readings than when I had the cats replaced. But with 275,000 miles on her she does have a tendancy to sit in the garage and not get driven a lot. The tech suspected carbon build up was the problem.