1991 300sl mercedes benz stalling out when warm

I have a 1991 300sl Mercedes Benz which starts up great and idles great, but when the engine warms up it then starts to sputter and eventually dies out. It will not restart again until the engine has cooled off. Any suggestions as to what might cause this...ust need to get an idea of where to start?  Thanks and any help would be appreciated. JT