My air/fuel mixture tower is still intact with the sealed ball and I intended on keeping it that way as much as possible. The 50% duty cycle I got was at idle; I forgot to measure at other rpms But remember my O2 is brand new.
I can rig the car where I can read the current to the EHA and the voltage from pin 3 on the test pod but the car does not have any issues while moving (as far as I can tell).
The current on the EHA when the car is warm and idling fluctuates between +1mA and -1mA. Does that help?

As to intake leaks, believe me, I went through this think in every way. The only leak I have is at the control valve for the heater unit inside the dash. That one is so small that I wouldn't think it would have such a dramatic effect as to stall the car.