Yes, a misfiring engine will run very rich.
I'm not advocating that you drive it with a misfire!
I'm saying that you may let it idle a bit to see if the misfire settles.
Sometimes you may have a bad connection with one particular coil pack which will give you a blinking CEL.
You should stop but let the car idle a bit to see if it goes away. If it settles down you may drive it at reduced load until you get it taken care of.
To do damage to the cats you would have to drive the car for many hours in those conditions.
The cats also can clean themselves when the engine is running well.
The heat they generate will burn off most of the extra fuel (richness).
Happy Bolstering,
Pedro
Pedro Bonilla1998 Boxster 986 - 312,000+ miles:
[www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)
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