When I start my 380sl (1982) the first time, the engine runs fine and I can drive the car easily. When I stop the engine and start again then the engine does not run fine, holds back, makes a different sound (kind of plopping) and when putting the gaspedal down more then the engine stops running.

Fuel pump has already been replaced some time ago and the connectors of the electronics near the engine are checked.

Can somebody help me ? Any suggestions ?