Apart from the previous replies which all have merit, don't discount that what's often needed to prevent chronic stalling problems with LH 2.4 systems is a simple cleaning of the throttle body, idle air control valve and flame trap. Changing plugs, putting in performance ignition wires, using a higher octane gas or even misguided attempts at raising the base idle can all mask what is basically a dirty or misadjusted throttle body (misadjusted here refers to the throttle stop screw, the throttle position sensor microswitch and the throttle control linkage). As the engine comes to (or leaves) the idle state, the transition of air intake control from the throttle plate to the computer controlled idle air system must be smooth for proper operation to avoid stalling or hesitation. The amount of air going around the throttle plate at idle and proper TPS microswitch operation are the basic keys to this transition. Naturally the rest of the engine system needs to be in proper working order as well which means a good spark and fuel injection pattern as well as properly working sensors such as the AMM, block temp sensor and O2 sensor.