There was a slight exhaust leak just ahead of the catalytic converter. I tightened it up, stopped the leak, but the car still stalls constantly and smells at a stop.

 

The leak could have fouled up the converter. You should remove it and check the convertor tubes for damage and/or blockage. If you shine light through one end you should see it fairly strong through the other whenlooking straight-on through.

 

Do an oil change and smell for gas in the old oil. This would be a sign of gasket or block damage. Gassy smell in your radiator is also a bad sign.

 

check the wire to ayour O2 sensor on bank one maybe one has broken or come undone which would let the car think its lean on one and then way overfuel....which will clog your converter, maybe you even gto a bad O2

 

Oil smells ok and I don't really smell anything unusual in the antifreeze. I did trace the wires on the O2 and they look fine, no breaks etc. Another guy suggested it still may be a vacuum leak on the back side of the throttle body. He suggested placing a small hose on a propane tank, starting the engine and slowly open the valve on the tank just a bit and move it all around that throttle body and the attached vacuum lines. He said if the engine idles out smootly, I found the leak. Sound plausible?

 

Yeah. That will work - just don't let it suck too much propane for too long. If it does even out you've got it nailed. If not I'm going to say that I just don't trust the converter. Especially if there was a leak ahead of it. That tells me it could have had the time to pull a good amount of debris and dustinto it.