1995 Nissan Sentra looking for suggestions

Here is my question my car drives fine for the most part. Lately some times when I drive and i'm like at a light, stop sign, anything that puts me in in neutral. The engine will sound like it wants to shut off but rev up again but then some times shut off. When I start it up again it will start back up just from time to time it does that.I put fuel system cleaners the one you put in the gas tank thinking maybe I just had some bad gas. It'll be fine but then it goes back again I forgot it even backfired once.I'm thinking sparkplugs mabey even fuel pump already changed fuel filter what do you think it may be.