What's the rotten egg smell in my car?

My 2010 Toyota Prius has been stuttering and there's a rotten egg smell. I've sent it to Toyota for repairs. What could be the problem?
The catalytic converter is producing hydrogen sulphide, a colourless gas with a foul odour of rotten eggs. It is very poisonous, corrosive, and flammable. The reason will be a combination of the type of use you put the car to and the quality of petrol you have been using.
Answered by Honest John

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