One thing after another ..... whilst awaiting return to Austin to try to get to bottom of the Death of Revs at 3-4 thou rpm - a SCARY thing when it happens .... i smellt a suplhur smell today and then heard a rattle suggesting either i had collected a tin can or perhaps an exhaust mounting had dropped off ... nothing was draggin on the road. After stopping then restarting, the smell and the rattle had gone away ... So my helpful online pals, how do i know if it is a cat and if so which cat has gone and how much are they to replace? Part cost and time to repair?