Hi,
What are you reading your codes with?
P1955 is a generic Glowpug Relay code, which in MB language is 2545.....see here :-
http://www.bba-reman.com/forums/Topic135536.aspx. This ended up being a Throttle position Sensor.
P0087 is Fuel Rail/System Pressure - Too Low, indicating a fuel system problem.
Steve