1991 BMW 318 stalls when cold

starts up fine idles at 1000 sometimes jumps from 1000 to 2000 sometimes stays at 2000 then drops a little stays running most of the timei can drive it no problem when i push in the clutch when down shifting or comming to a stop it stalls theres hoses under intake manifold that conn to a hose on the front left of manifold that are kinda cracked but not chure what is part number or what it is called i also have central locking problems is there something that holds voltage on that sys it sat for awhile i diss conn batt gnd when i reconn they did not work drove it around for 40 miles and they worked let it sit over night and they did not work any advise will help thank you and alohaz