It sounds like you have a worn key or tumbler assembly. Try a different key to see if that can be the problem if not you will need to replace the ignition key tumbler. You will need to remove the steering wheel.
Here are diagrams to help you get the job done.
Check out the diagrams (below).
Please let us know what happens.
Images (Click to enlarge)
Monday, April 23rd, 2018 AT 1:01 PM