Once a week or so my car doesn’t start right away after I have driven some where, such as to get coffee, the library, or shirts from the cleaners, It makes noise as if it will start, but then gives up. If I sit and wait patiently – doing nothing for 15 to 20 minutes or so, it will start. The mechanics have checked it over several times, but can’t figure out what’s wrong. They suggested putting in a new engine relay a week and half ago. Since then, the problem has happened twice.