Bad ignition switch?

I have a 99 frontier 4x4 kingcab 3.3 auto. I have been having problems with what I believe may be a bad ignition switch. If I shut the truck off quickly or in normal fashion it will start running again when the key position gets to the lock position, as you continue turn it back towards you it will shut off. There have been times when I get in the truck and the ignition lights are on and the key is still in my hand. There have also been times when the theft alarm goes off. I was sitting in it the other day with the key out and the ignition lights and relays would click on then off. I think that I will try a new ignition switch first ( the electrical rotory switch) not the key cylinder. It has 170k miles.
Anyone else have any experience with this?
Thanks!

I replaced the switch with a OEM, $47 and very easy to change and works great now!