I know that a "too rich" car can burn-up a catalytic converter because fuel is mixed-in with the exhaust and that this heats the catalyst thereby melting it. Suppose you had a car running very rich-- say at 4 or 5% CO. You can smell gas from the exhaust. How many miles of driving like that do you think it would take to burn-up the catalytic converter? 10 miles, 100 miles, 1000 miles, 10,000 miles?

I think the answer is that it can burn-up in a few hundred miles this rich. But another person disagrees and says it should take thousands. Anyone with any thoughts or experience with this care to comment? Thanks