My 1995 S420 starts easily from cold. But if I drive only a short distance and park for a short time, it doesn’t want to start and run. It will crank and sometimes backfire. If it does start, it will not stay running. If it sits for several hours, it fires right up again. If the car is driven for some distance and parked, the problem does not occur. It only happens when started from cold, driven a short distance and then parked for a short time. Any ideas where to start looking for the problem? Car runs perfectly in ever other respect.