98 Grand Am Stalling Problem

My daughter has a 98 Pontiac Grand AM....2.4 lt engine....about 83,000
miles on it.


It is having a problem with intermittent stalling.

I replaced the spark plugs and cleaned the idle air control motor.  It
didn't stall for a week..then started stalling again.

I replaced the idle air control motor.  It didn't stall for a week.

I replaced a defective vacuum line from the throttle body to the map
sensor and replaced the fuel filter.  It didn't stall for about two
weeks....thought I had found the problem.


It is back to stalling....several times a week.  75% of the time it
stalls when it has been driven a short distance....perhaps a few
miles....so the engine is warmed up...shut off....come back  10
minutes later....like after running into a store...when she restarts
it, puts it in gear, steps on the gas to go....it stalls.  Usually, it
restarts no problem.


25 % of the time it stalls after a cold start....brief warm up...put
it in gear to back up....and stalls.


Any suggestions?