Great Car, Comfounding Issue

My daughter’s 93 MB 300SL with 101K is a smooth beast and hums and runs like a dream. However, without warning, it will attack and act like it is running on dirty gas or a failed plug or plug wire. Just as suddenly it will calm itself and turn back into the glorious beast it was meant to be. Weather is no factor but it is mostly used just to run around on errands and not taken to the track and asked to express its true dimensions. No diagnosis has been able to satisfy.

Has anyone given the fuel system a good look?

I will forward this to her but I did suggest she run some Fuel Injector Cleaner through the system.

Good suggestion. I was thinking more of changing the fuel filter and testing the line pressure and pressure regulator. While other possibilities exist, the symptoms are typical of sporatic loss of fuel. Gotta start somewhere.