Automatic question

It certainly is possible to stall an automatic! My Merc does it at times. Idle air control valve is usually a suspect, but if it only does it when cold, then it's a cold running device - I'm not familiar with Fords at all so someone else will be more accurate I expect.

it's probably the brake on/off switch you need to get this sorted because it rises the idle when you put it into gear, and also turns it on when you put your foot on the brake pedal although you don't say what year it is so there may be other reasons

Does it ever stall when she puts it into D/R?

Si

You what? Since when has a brake switch affected the idle? This is done by ECUs on modern cars. Older autos just had the idle set higher than manual models.

you have obviously never put a Granada 24V engine into a sierra before have you they use the BOBO switch to up the idle otherwise the engine stalls everytime you lift off and come to a halt it's a known acknowledged phenomenon about an engine that was never designed to be fitted with a manual gearbox