In the datastream mode I'd suggest monitoring the voltage readings of all the oxygen sensors, as well as the coolant temperature sensor, MAF sensor, and TPS sensor. If you can capture what those readings are just before, during, and just after a stall, that might point us in the appropriate direction.
If you can get this data and post back on this thread, we'll see what we can do. Others may have some additional suggestions as well.
-Rod