sharan carat 1996 wont start some days?

my sharan starts , but next day it takes 4 attemps to start,usually first time every time.it will turn over ok but none starter.If it dosent start first time,i open fuse box door ,and wait for a click, when i hear this i know next time it will start. I have changed fule relay to no joy, only thing its not consitant it might go ok for a week then play up. Only 4years ago a power relay went same symptons,will this electrical relay as well.