Treasure

The problem I am having is related to starting my 07 JK and twisting the key to start it...if you press in toward the steering column as you twist the key it sometimes just barley fires the starter and stops (engine does not fire up) or once in a while is stays stuck in the start position after the engine has fire up (starter still engaged while running Not Good)...here lately after it is driven around town and shut off and then re-started it just does the partial crank of the motor but not enough to start it.....I have notice that when it does this I can shift from park to neutral and it will start every time.

Can anyone tell me if I just need to get the actual tumbler unit where the key goes replaced or what you might think it is?
Thanks