catayltic converter smell

[BlackXC90T6AWD]

After driving on the highway for a while and passing some trucks and people in the middle lane going to slow my cataytlic converter starts smelling more so then usual then i get a check engine and engine system service required light the engine still runs fine but should i as we americans say put it to the floor it starts stinking up the joint agian. I know that they are suppose to have that smell every so often but this is mroe then normal. anyone got any idea as to whats going on anyone experiance this?