The exhaust fumes from a garage in a place that uses petrol of high sulphur content are bound to contain?

Petrol burns in a limited supply of air in an engine, so some carbon only burns to carbon (II) oxide, CO.

Sulphur in the petrol burns in oxygen to give sulphur (IV) oxide: S + O₂ → SO₂. So the fumes contain CO and SO₂.

Hydrogen sulphide (H₂S) is not formed because the fuel is burnt in oxygen, not reduced. There is no source of chlorine, so no HCl is made.