My 1998 honda civic is messed up has a vtec head and a non vtec bottom it keeps shutting off and won't run sometime what can i do

I have a 98 civic ex with a non vtec
bottom and a vtec head. It keeps
cutting off when driving and sitting
still. Then when it cuts off it won't
start sometimes them sometimes I
have to wait and it will start rite up. I
don't know what to do I replaced
battery distributor cap and ignition
coil