Spluttering on start up?

Hey guys, I have a 1.6 mk2 mx-5. It has only started recently when the engine is hot. If I stop the engine and start it again (still hot) it will start but the idle will hunting from 500-900rpm, if I drive it I have no power and the engine sounds like a Subaru. It will then usually after a minute or two go back to being totally normal. Anyone have any ideas what this could be? It's getting to the point where it happens every time I start the car while the engine is still hot.