1989 Mercedes Benz 300e gas dripping under car

Okay, I had the same issue.
If its from behind the driverside front fender, its your pressure regulator canister.
You can replace this with a canister with any other of the same type. (Even if one has 2 tops instead of 3. One of your hoses just leads to a whole in the body. Useless)
if its from under the engine, check your pressure regulator. Its under the air filter box. Small can looking thing. The tiny hose on the end of it tends to break off. Causing a hard cold start.
From any where else, check your fuel lines leading to the engine.
Fuel tank is between trunk and back seat.