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Hello, thanks for posting here
The stalling is most likely caused by a throttle body that has too much carbon built up in it, i assume that the battery was disconnected when replacing the alternator as I should be, this can cause a stalling problem because the computer will set the throttle plate to the factory default setting, the carbon deposits in the throttle body prevent this from happening so a stalling condition is the result.
The remedy is to remove the air intake hose from the throttle body then open the throttle plate and clean the carbon deposits out using a can of spray air intake/ throttle body cleaner and a stiff brush (an old toothbrush works well) make sure the battery is disconnected before starting the cleaning, after the carbon is cleaned out reconnect the battery, start the engine, rev it up to blow all that stuff out the exhaust and drive it for about 15 minutes or so, this should take care of the stalling.