300E Stumbles and Stalls after a mile or so

[Springbank]

I have a 1989 300E Euro with a five speed. I tore my knee up, and was unable drove a stick for about 7 weeks. When I got back in it, it would start and run fine for a mile or two. Then, when the temp gauge is reading about 80, if I let the car idle, it will start running real rough, and eventually stall. If I can drive it past that point, or if I can keep it reved to 2500 or so, it warms up further, and will idle fine.

If it does stall, it won't start, and the engine bucks when you try. After sitting for 15-20 mins, it will start and run fine.

Any ideas? I'm getting real sick of this.