Grand Voyager, 1998, auto transm. Problem occurred a couple
of evenings ago - I was in a store's parking lot,
put in the ignition key, and it wouldn't turn.

(Tried a second key I had also).

Figured it was an interlock issue, so tried shaking
the transmission lever, moving the steering wheel,
etc., but no good.

A friendly mechanic suggested rocking the car (by
hand) back and forth, and that worked...

I got home and hoped it was a once-only event. But
the next morning it happened again (not as bad, though,
and I was able to start up again).

Can't get to the shop for a couple more days, so what
I've been doing (cover your eyes before reading...) is
_leaving_ the key in with the ignition set to "off"
rather than "lock", and using my other key to secure
the door. (fortunately my main parking spots are
private  enough that this s ok).

Related problem is that this drains the battery, but
I can deal with that if needed.

Any suggestions as to how much work fixing this
(and how much money...) will take? Thanks muchly.