Catalitic Converter or something else?

I can't imagine anything with the catalytic converter would cause your issue. What color was the exhaust?

The cat is usually closer to the muffler which makes me rule that out.. but I am no car mechanic.

Maybe that's oil or ATF leak onto the exhaust. The converter is quite a passive device and should cause the problems you described.

How's the fluid in the power steering reservoir?

Maybe that's oil or ATF leak onto the exhaust. The converter is quite a passive device and should NOT cause the problems you described.

How's the fluid in the power steering reservoir?

Also, how is the belt tension for the power steering pump?

Maybe a burnt spark plug wire causing your engine to miss a beat?

Noises are difficult to diagnose without hearing them first hand, but the rough idling and noisy could be due to an exhaust leak. If the catalytic converter was aftermarket, then there is a higher chance that it is leaking than if you used an OEM part.

Even an exhaust leak should not produce smoke unless the engine is really running very poorly or something is dripping on the hot exhaust. The hum when you turn the steering wheel can be from the power steering pump. Check the fluid level in the power steering reservoir. If it is low, then you may have power steering fluid leaking on the exhaust or engine somewhere. Topping off the fluid should quiet the pump, but it is dangerous to have PS fluid leaking on something hot enough to make it smoke. I would have the source of the leak identified and fixed before you end up with a fire under the hood.

Thanks, guys, for your input. Especially Ray. You were right on the money: catalitic converter, PS pump leaking. All those terms you used helped me look like I know something about cars and not a complete ignoramus in that area:o). Thanks a lot again. I'm glad this forum has guys like you hanging around.

You're welcome! Glad to be able to help.