from the sound of what you are saying try this ,, i do believe i said this in a post on this page. next time you start cold turn on the key ( not into start,,count to 10 turn off the key,, turn on the key count to 10 turn off the key Now start the car if the filter lets the fuel drain back it takes this system to get fuel to the injectors and it get the air out, try it you may find it will work,,, if it does go to Mercedes or Chrysler and get a new filter and or pump. jim

ps 6 seconds is not enough