Mercedes: 1987 560 SEL Wont Start on First Try, cold start, fuel rail pressure drop

Question
The car was stalling and eventually didn't start. I replaced the fuel filter and fuel relay and it runs great -- except. When it's cold, it will start for a second and die. On the second try it starts right up and runs like a dream. When it's warm, it start the first try.
Any ideas?
Thanks much!

Answer
Larry,

I suspect that the fuel rail is leaking down when the vehicle sits long enough for the engine to get cold. It is a function of time not temperature. The injectors may be weeping. When the fuel gets down to less than a quarter tank, I would purchase a bottle of Techron injector cleaner, fuel additive and fill the the thank with the highest grade fuel you can find. Preferably without ethanol. It your still have the problem then it may be the fuel rail back flow valve. This valve is suppose to keep fuel from leaking back to the fuel tank when the vehicle is shut off.
Additionally, if you have not replaced the plugs recently, I would also install new spark plugs.
Good Luck and let me know how it turns out.
Rob