Take off all of the connectors and reinstall them. The main controller of spark comes from the black unit mounted to the driver's side inner fender. It is beside the air cleaner mounted to the fender inner.
There is one plug that is the crank sensor, without it, the car will not start. Take all of the connectors off and spray electrical cleaner on them and reinstall. IF this doesn't work, I would take off the coil wire from the distributor cap and install a plug in it. Crank it over and check for fire. If none, check the ignition coil. If you do have fire, replace the cap and rotor.
I would really suspect a crank sensor if you have had a stalling problem in the past.
Take loose the battery for a half hour or so also..
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS