[robs]

1) Remove the big rubber boot on top of the CIS. Check if the airflow sensor plate and the throttle flap are clean and move easily.

2) Remove the decel valve behind the throttle body. Connect a vacuum line on top, suck and pinch it off to keep the vacuum. The idle air bypass must be open now. Release the vacuum: the bypass must close in, say, 1-2 seconds.

3) Motor off, ignition off. Release the residual fuel pressure (for example, you can loosen one connection of the fuel filter). Now lift the airflow sensor plate by hand. The control plunger must move easily inside the fuel distributor. Let the plate come down again and feel if the plunger follows.

4) Check the microswitch at the throttle housing.

5) If you have a catalysator, unplug the O2 sensor to get a fixed duty cycle for the control pressure frequency valve. If the high idle disappears, the closed loop control may be faulty (I don't think that's your problem, I just wanted to add an item #5)

Hope that helps,

------------------
Robert / 80 Targa