2004 pontiac grand prix GT2 cranks but won’t start

I have a pontiac grand prix that we have replaced all
the coil packs, the ignition control module, all the
spark plugs, fuses are all working, put on new battery
terminal because it was super loose. it will crank but
won’t start every time. sometimes you go out there it
starts right up and runs like a dream then you turn it
off and go to start it and it won’t. we used a scanner
and the only codes it was throwing was the ignition
control module and the crank shaft sensor. before i
throw more money at this pile of crap would replacing
the crank shaft sensor fix it or is it more than that?
thank you for the help in advanced.