engine stalls when hard braking

this pertains to a 1996 ford ESCORT LX sw, w/ at, ac, 230000 miles:
recently during the last few months whenever i'm travelling at between
20 and 40 mph and i've had to brake very suddenly and very hard, the
engine stalls as soon as the car comes to complete stop. never used to
do that before. engine starts up w/o any difficulty afterwards. a/c
is NOT on when this happens. engine does NOT do this when i brake
normally, i.e., non-panic stop.
any ideas on what's causing this and what components to check? any
advice would be greatly appreciated .....
tia.