Mercedes Benz repair: cold starts, fuel pressure regulator, fuel pump relay

Question
sir i have 1988 560sel hard to start when cold will start then die start fine when hot also seem to have loss of power when driven thank danny 16 year son want to start driving   thanks danny

Answer
Possible issues:

Corroded wire connector
Altitude Sensor
Cold Start Valve
Cold Start Valve Gasket
E.H.A. Valve
E.H.A. Valve Seal
Air Mass Meter
Fuel Injector
Fuel Injector Seal
Fuel Pressure Regulator
Oxygen Sensor
Throttle Body Gasket
Water Temp. Sensor
Fuel Pump
Fuel Pump Check Valve
Fuel Pump Relay
Overload Relay
Alternator
Distributor Cap
Distributor Rotor
Ignition Coil
Ignition Wire
KE Control Unit
Reference Sensor
Spark Plugs
Voltage Regulator

I suggest you join:
http://www.mercedesshop.com/shopforum/forumdisplay.php?f=1

This is going to take serious diagnostic time, and many posts to resolve.
You may be fortunate enough to have several forum members near you.