Codes

I got my codes and came up with a 13(o2 sensor) a 42(ambient air temp)and a 51(I forget what this is) My question is,the ambient air temp is in the ecm according to the haynes manual,but I removed the box on the side of the carb that controls the ? idle? It bolts to the drivers side of the carb/throttle body and has a plunger that is electronically driven and runs to the throttle linkage.With that missing will I pull codes? The car runs fine without it and whenever I try to put it back the idle will go from 500 to 5000 and back every few seconds.Any suggestions would be appreciated,Also if anyone has this particular part I might be interested in buying one.
Thanks