Let us spray. 1  When you're at the perfume counter, buying something smelly for your nearest and dearest this Christmas, just don't ask what's in it. 2  When you're at the perfume counter, buying something smelly for your nearest and dearest this Christmas, just don't ask what's in it. Hannah Betts argues you may get a nasty surprise.
Best Answer: When a catalytic converter goes bad it will restrict the flow of exhaust gases through the exhaust system. Basically, if the exhaust won't come out easily, air won't be taken into the engine easily to mix with the fuel to be burnt and give you power.
If an engine is running well, there isn't really much for  the catalytic converter to do. If the engine is in need of a  tune-up, the catalytic converter may get quite a workout and in the  process it can get very hot. Also, deposits can build up on a  catalytic converter, making it useless.