well Iam thinking you are going to need to change the steering lock assembly.
The spring part that returns it from the start position would be in this part and not the lock tumbler.
look in the buy parts tab above for your yr model. think it is $112.
replace it before it totally quits.
I replaced this part about 6 mo back. I thought it was the tumbler, but after getting it from the dealer, still had the problem,
ordered this from Phill, and it fixed the problem.
Charlie