need help

ok I have a 88 civic it has a few problems I cant figure out. 1st some mornings it will crank crank crank and will not fire some times it takes a few minutes and it will star up and run with no problems. Some days it will not start and I get home from work and it will start right up. 2nd it some times when if fires up it will spit and sputter until u get it up to about 3000 rpm some times it will not do it until u drive it about 5miles and u try to take off from a stop. I have tried a few things I have but new plugs and wires on it. I put new fuel injectors in it and the o2 censor is 2years old not sure what to do please help :runaround: