Runs for five seconds then dies

every time i use my air conditioner or the fan in my car and i come to a stop it dies down on my rpms and it almost stalles out. do you know what the problem is ?

was the A/C recently repaired? an over-charged A/C system (too much refrigerant) can cause engine to stall with A/C on. also have the charging system tested. the A/C draws a lot of power from the engine which also puts a strain on the charging system, if the alternator is weak then it may not be able to handle the extra load.