190e, 2.3 occasionally will not start / stalls when warmed up

[Sven Berkemeier]

1991
Mercedes 190e, 2.3
Automatic
180000 miles


Car cold starts no problem.


RANDOM PROBLEM:

SCENARIO 1:

- when car has been driven, parked, then while attempting to start it, it will start then immediately shuts off
- attempting to restart it, it will not turn over
- car has to sit for 10/15 min. and will then start after several atempts
- on occasion the battery has been drained while attempting to start the car

SCENARIO 2:
- the car has occasionally stalled while driving. In order to restart it, it will go through the same steps as in Scenario 1.


THINGS TO KNOW:

- Problem has existed for approximately 9 months.
- Fuel Pump and Fuel Filter were replaced 6 months ago.
- Problem continued, first less then more frequent (un-predictable).
- Mechanic then drove the car for 60 miles and could not duplicate the problem.
- Spark Plugs were just replaced.
- Problem continues.

Do you have any advise?

Best regards,
Sven Berkemeier