HELP Stalling 97 Dodge Stratus

We recently purchased a used 1997 Dodge stratus, it has stalling issues. It does worsen when the temp outside is cooler. we have had a tune up done on the car. and still the stalling continues. One added note the car does have an aftermarket car alarm installed. and sometimes, refuses to cooperate. ( alarm goes off for no reason. not sure if its related at all. Any help would be greatly appreciated


Thank You