Timing belt was replaced at around 120,000 km. Cat trouble may be possible due to rich mixture, both O2 sensors have been replaced (I did one myself-downstream, and it was oiled up pretty good, as were the plugs when they were changed) I wonder if the crack in the ex. manifold has been allowing oxygen into the exhaust gases, and fooling the computer into thinking the mixture is lean?
I'll clean it all up soon and get back to you..
