Fuel pump?

Ford Taurus 2003 stalls while stopped for traffic lights

throttle has been cleaned

fuel filter replaced

car still stalls

mechanic has done the computer analysis and is still baffled

The problem might be with the Idle Air Control motor circuit. This component is mounted on the throttle body, and as its name implies, it controls the engine idle speed anytime the accelerator is released. One way to find out if this is the problem is, when you feel the engine is about to stall when coming to a stop, slightly step on the accelerator while applying the brakes. If doing this prevents the engine from stalling out, have your mechanic check out the IAC circuit.