Cold/Hot Weather Idle?

I have a 1993 Toyota Paseo, 5 speed stick with 223K miles that's still going strong. Over the last year and a half I've had an EGR valve replaced, changed plug wires, plugs, replaced fuel filter, etc. When the weather hits extremes I have an idling/stalling problem. In cold weather it hates to start. In hot weather it starts fine but often when I press on the accelerator from a dead start (at a light, ie) than it stalls out. In moderate weather it runs fine. Any ideas?