kodoq39, sounds like a bad crank position sensor to me.

When the ignition control module went on our daughter's 1991 300CE the engine would not start at all. From your description your engine starts, but won't stay running. Ignition control modules are very expensive (around $2,000) so you don't want to arbitrarily replace it. Hopefully it's something far more simple and less expensive like the CPS.

The best way to ensure longevity of the ignition control module is to regularly replace the distributor cap, distributor rotor and spark plugs ... say every 30,000 miles ... plus check the ignition wires for signs that they need replacement. Weak ignition components stress the ignition control module causing it to fail.

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Fred Hoelzle