Rotten egg smell coming from 1995 cougar?

A rotten egg smell in your 1995 Cougar typically indicates an issue with the catalytic converter or a problem with the fuel system, such as running too rich and producing excess hydrogen sulfide. It could also suggest a malfunctioning fuel injector or a problem with the engine's combustion process. It's advisable to have the vehicle inspected by a mechanic to determine the exact cause and avoid potential damage to the exhaust system.