If they really want to hurt the Iranians they should put a gas embargo in place and bomb their refineries. They can still export their oil, they just don’t have any gas for their economy.
Sink Kharg Island.
That is a really great idea. Embargo them on gasoline and diesel. Blow up their own refineries. Their internal economy would collapse(worse than it already is and potentially a full blown revolt/revolution). Allow them to continue to export crude to keep the Chinese happy.