When it does start it can crank over and stop mid spark.On occasions that it refuses to start it omits a low (excuse the description) "ugh" and no spark or any intention of sparking. Starts when I leave overnight.One method I had been using which appeared to work until last couple of days,was taking key to half way point,pumping the gas then cranking the key fully in the barrel.Now that isnt working.Am wondering ignition connection? Thanks for your help.
No warning messages on dash.
Have booked in for full diagnostic with mercedes garage next week.Thanks for your help.