Being that it only stalls out when the accesories are being used, I would rule out fuel and concentrate on electrical. Did you do a test the voltage at the bat to see what it dropped to. These damn computers need a certain amount of juice to properly work.
Here is a quick way to test.
Some EEC relay diagnostics: here’s a place to look. First check the PCM/CCRM fuse in the underhood fuse box (20 amps). Also check the ignition switch fuses.
At the CCRM (Constant Control Relay Module – the black box mounted on the radiator overflow bracket): With the key turned to run, check Pin 12 and 24 for accessory power. If it’s there, the issue lies past the CCRM. If there’s no power: Check CCRM Pins 8 and 10 for constant 12 volts. Check CCRM Pin 13 for accessory 12 volts. Check CCRM Pin 15 for ground. If 8, 10, 13 and 15 are present (this requires the key to be on), but 12 and 24 are not showing 12 volts, that suggests a bad EEC relay inside the CCRM.
If you want a real easy way, remove all fuses for ac/radio/ etc.... If the problem continues then I would do the above. Keep me posted cause I have a few more ideas but need to know this first.