i had the same problem.turns out it was the ground from the starter relay. the neutral reverse on the transmission has nothing to do with it. it does not have to be hooked up to start and run.my ground LOOKED grounded but it was not. take the ground off and run a whole new wire to the body and see it that works.i was also able to jump it off the starter relay. i dont know if this is your exact problem,but a mere suggestion.