If you hit the air intake with a dab of either it starts and runs perfect. Also starts great after warmed up, it seems to have low fuel pressure on cold starts
My 560 sel starts very hard especially in colder weather or after it sits . on 1990 Mercedes-Benz 560SEL
check your fuel pressure when it is cold
Fuel pressure is very low if any until the motor really gets cranking or engine is warm then it is fine. Waht would correct that situation?
a new fuel pump