On the 1970 thru 1975 V-8's with fuel injection it is VERY common to have fuel leaks at the injectors. WE always replace all of the rubber hoses whenever any of them leak(FIRE). Have seen "many" of these engines catch on fire, MB even had a recall back in 1975 to replace all on the rubber hoses & they were only a few years old then!!!
The idle problem is related to the additional air valve.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)