My son's 98 lsc randomly turns on and off. It begins with various check messages like check headlamps,low fuel level,traction control and sometimes others.When traveling the instrument lights and engine will go on and off, but headlights will remain on and car will buck sometimes depending on how many seconds the engine is off when it begins to run again.When it does it at a redlight the car sometimes completely shuts off,but starts right back up.It usually does this at random times but several times in a row when it does.Ran a scan and no codes showed up.Car has 140,000 miles and runs good when it is not acting up. I am concerned about my son running into a safety issue and would appreciate any ideas you could share. Thanks,Scott