2002 Honda Civic Engine revs up and down while stopped

I have a 2002 honda civic ex with manual transmission. My problem is, while stopped at a red light or just parked with engine on, my engine will rev up and down from about 800 rpm to about 1100 rpm. Also while driving and going through each gear, I feel a little hesitation while accelerating. If I floor it it's not giving me all it's got. And there has been a couple of time that the engine has turned off while driving and while stopped and it would take a little bit before it would start again. Any help would be greatly appreciated.