Engine miss - Injectors working?

[michaelsellars]

Hello,
I recently purchased a '73 280sel 4.5 and need a little help diagnosing a problem. The engine has a miss at idle and at lower RPMs. I have narrowed the problem down to what I believe is a fuel delivery problem. With the car running, if I disconnect the spark plug wires from 4 cylinders, (#2,#4,#7,#8) there is no change in engine performance. Spark is good to these cylinders so I am guessing my next step is to verify fuel is getting to them. Can anyone please tell me how to check that the injectors are working properly? I do not think they are getting voltage from the control unit. -Mike