Hot water tank only works half the time

Hi guys new here and looking for some help. My hot water tank only wants to fire on LP maybe half the time. One day I can flick the switch and it fires instantly and works fine then nothing won’t start no matter how many times you try. Come back in 4 hrs and bam! Fires up or sometimes won’t start for days! . Gas pressure is good , spark is good , no clogs , battery’s good. I thought it was the reset thermal fuse so I bypassed it with no luck . Then I bought a new gas valve and same issue . I’m thinking it could be the control board any other ideas??