1992 lincoln mark 7 starts good but when i turn ignition off it wont shut down

Hello, the last of the really great Lincoln Mark's! The Mark VIII was an interesting car, but the Mark VII was solid and had the venerable 302 cubic inch engine still, for the very last time. Your concern sounds like it could be related to the ignition switch - the electrical one - in the steering column. Some of these were even included in recall 95S28 -- I'd imagine yours would have been repaired by now; that was issued 25 years ago. The key cylinder could be a concern also. Hard to know for sure without performing some hands on testing. See the link below if you'd like to find a shop near you to help out. www.repairpal.com/repair-shops Good luck!