Midas agreed to replace the muffler & Cat they installed 34,000 miles
ago, but stated I would need to get the engine checked as "convertors do not
wear out".  I asked for specific things to look for--and he stated the
either the O2 sensor or an engine that "runs too rich" could prematurely
burn the cat out.
Any truth to this?  and if so, what might the procedure be to check out O2
functioning and/or "richness"?
TIA,
Jim