1997 Mitsubishi Eclipse car acts funny

Ok my car is a 97 eclipse with 117000 miles. My problem is the car at certain times it like shuts off but keeps going. Like when it sits and is idleing it will sound like it is going to stall but then all of a sudden it will start running fine. Or when im driving it will all of a sudden like quit worikng but it will keep running. It stalls out is what it feels like but it keeps going fine if you dont push on the gas but if you do then it will keep doing it an even worse then what it was doing it before, but once you stop then it will go back to normal. Can some one answer this please an thanks