Idles @1800rpm then dies when hot?

[scw13402]

72 914 1.7 Fuel inj. When first starting it idles at around 1800rpm Even after driving for 10 -15 minutes it will still idle at around 1800. Once the engine gets good and warmed up and hot after driving for a while, the idle speed drops to nothing and car dies unless I keep foot on the gas. I don't think it's a vapor lock issue because the car will run fine when hot. It just won't idle. Idles fast when cold,,,won't idle when hot. Any ideas?

Thanks