I have a mercedes 230CE made in Europe 1984, altho' they were not officially made that year. It was specially made for my father. The engine quit without warning, would not start. My husband did work and determined the fuel pump is working. A new filter is put on, the fuel pump "buzzes" when the key is turned on, which should indicate that fuel is being delivered. Now the engine runs for about a half a minute then suddenly quits. This occurs repeatedly with the engine always quitting in short time. What else could the problem be?