I purchased a 1995 Buick Le sabre two years ago.Not even having it for a year or so I started having problems with it.It would cut off on me and sometimes it would start back up.and sometimes it would take a hour or so for it to start back up.I bought a new battery.someone switch the computer out.Now it doesn't even start up someone told me I may need another starter and that I have a oil leak.what can be the cause of this problem.when I had someone look at it last year and they stated there was nothing wrong with the vehicle.which didn't make sense because it would just just shut off on me.I don't wanna keep put money into it when people say its one thing and then I switch out the parts and still have the same issues.i wanna sell it.because I can't keep putting money into it and have it shutting off on me