Accord prob.

I have a 99 accord ex, manual. I have been having a prob with starting up. Sometimes when i crack over it revs up then starts to cnock out then dies. crank it about 5 times then it starts up no prob. Today I cranked it up, after i have been drivin it for awhile. Anyways, it started conking out then dies, then i cranked over tried to start fired up then died. Please help!