Start with the simple things. Replace the distributor cap and rotor and plugs if you haven't.

Be sure that the fuel pump relay is new.

I have seen this symptom caused by 3 major components.
crank sensor
coil
fuel pump relay.

Good luck

I have not replaced a 300E EZL yet.

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS