Mercedes Benz repair: 1994 Mercedes sl500, mercedes sl500, correct direction

Question
Usually starts fine, sometimes shutter a little at first, but after driving for about 10 miles, either local or Freeway, it will stutter and die, and won't start for anywhere from 30 minutes to 2 hours.  Doesn't show any diagnostic codes when tested. Has 82000 miles, has been maintained well, had 60000 mile tune up.  Husband deceased now, can you point me in the correct direction for possible answers to what might be the mechanical problem of cause.

Answer
thia is odd if the car doesnt overheat it should start up as far as compression I would start with jumping the fuel pressure relay first and your OVP relay make sure those are fine.This is to check the fuel pump .  and sensors.Otherwise I would check the cam and crank sensors something is not right where it is ovverunning your car not to start so after a relay FPR relay check and OVP relay check I would definitely start there then I would check the cam/crnk sensores then the coils.. Start with the cheapest first.. then you work to the electrical then the mechanical