Germain,
  I have the same problem. I just disconected the idle solenoid valve.
No affect on gas mileage. Since I have no AC, and don't push the limits
on steering (4WD would hate that) and anyway I have a right foot, I have
never needed idle stabilizer function. The control unit is a very
expensive luxury.
    Stan 87 Syncro

Germain wrote:

> Hi all
>
> After opening my ISCU and changing the transistor and the 56 ohms resistor, the idle valve is humming. I have noticed that after turning the ignition key without starting the motor, the idle valve is humming for maybe 15 seconds and after it stops. If I turn off the key and try it again, the idle valve do not hum. Hum! Hum! (unless i try to start it the day after).
>
> Anyway I tried to start the motor and the motor started right on . I didn't have to play with the gas throttle. RPM was 1100. It was used to be 700 RPM with a lot of stalling before. While the motor was warming up, it started to surge going from 2400 RPM to 1400 RPM. I stopped it and restart it. Everything seem to be OK. I did a small ride with it and once again, it started to surge again. The motor was idling around 1500RPM and while I was braking, the RPM was going up and down. WOw when it is acting like this, you have to push hard on the brake while waiting on a traffic light.
>
> MY Question is: What could cause the surging? It is coming definitely from the idle valve or the ISCU. I was running for months without the ISCU working ( but I had rough warming up). Is the Idle valve usually closed when the gas throttle is pushed? and reopened when the gas throttle is released?
>
> Germain
>
>