ignition shutoff

The click you are hearing is the key lock mechanism releasing the key. You are having one of two problems. Most likely your neutral safety switch is going out. You can replace this yourself......BUT there is also a chance the key lock mechanism may be sticking (more uncommon but possible). Only way to fix the key lock going bad is to replace the ignition lock cylinder. But chances are you have theft-lock and air-bag. You cannot do it yourself. This task will have to be assigned to a mechanic.