2004 C 240 fuel pressure loss

[BENZ TEK]

Hi all!! I am hoping that someone out there has experienced this problem before. The case is a C240 that has a fuel pressure loss after two days of sitting without starting. If the car is driven or at least started everyday there isn't any problems starting the car. I confirmed that over the weekend with a fuel pressure guage connected I had 0 psi Monday morning. I tried to start the car and after the first tip start I recycled the key once more and the car started but ran slightly rough until the fuel pressure was equalized at all of the injectors. I think I may have a bad fuel pump not holding pressure after long periods of sitting or a bad filter in this case. I heard that some filters were designed to have the ability to keep fuel from bleeding back to the tank. I also noticed that when it started that there was more smoke than normal ( it seemed ) that was coming from the exhaust. Possible injectors leaking in the cylinders causing the fuel pressure loss? Thanks for any help in this matter.