stalling is not life or death issue. Nor does it damage your engine. It's just an annoying problem. Do simple test, start car, warm up until normal temp (means near middle of the temp meter) you can drive it around while waiting for it to reach normal temp (either aircond on or of). After reach normal temp, turn off aircond. Look at your rpm meter. What does it read? turn on aircond, what does it read. if RPM way higher with aircond off, your a/c load is not being detected or idle valve not working (due to tps or iacv problem) if not means it dips, then returns to normal rpm (just below 1000 usually), then it's likely mechanical, causing aircond load to be heavier from normal, causing your engine to stall.