Running rich

I replaced both O2 sensors a few months ago. Car ran perfect after that. Cleared all engine codes. Now it is smelling rich at an idle, and has an occasional miss. SES light is not on. Ideas?

PS-only two o2 sensors, because cats have been removed and holes plugged.

With no codes it's hard to say. Personally I'd verify the AFR with a wideband first to see where it's at.

With cats removed the cars will have what I call a more normal smell like a classic car would. Some feel it stinks and makes them think something is running rich when in fact people have simply gotten so used to the converter world that they have forgotten what a typical non emissions car smells like.

Speaking of which, when I lean a classic car out to about 14.0-14.5 AFR they actually smell worse, a rich fuel type of smell, and people think the same thing when in fact the car is running closer to stoich then what their nose makes them believe. They actually tend to smell a little better (sweeter) when I have the AFR's richer in the 13.0-13.5 range.

Today's pump gas doesn't help with smells either

I agree with FBJ but first check the basic things. Pull a few plugs and see if they are burning in a uniform manner, second make sure all plug wires are on firmly and you don't have and burn marks from shorting and last check the air filter. A clogged air filter will cause the AF ratio to be off but it would throw a code unless you have changer the settings.