2001 Isuzu Rodeo Dies When Stopping

My 2001 Isuzu Rodeo (auto trans, 120K miles) very quietly stalls when
coming to a stop, but only when in Drive. The RPMs just drop right down to
nothing -- no lurching, no rattling. If you have the radio on, you don't even
realize the thing died until you try to take off again.
If I drop into 3rd gear as I'm slowing down, I can bring it to a stop and the
engine will idle. I can also keep the engine running if I go into neutral.
I'm able to shift into drive and excelerate from the stop.
We cleaned the Mass Air Flow Sensor and the problem seemed to clear up
with cool weather, but the problem returns in the warmer afternoon outdoor
temps. It doesn't seem to have anything to do with the temp of the car, but
if it's warm outside, it's a constant problem. So the drive to work is fine, but
the drive home is hairy.
There are no engine codes--I had someone hook up an engine code
reader).
Otherwise a strong running car. Help!