440 Turbo idle problems

Having assumed responsibility for an early 440 Turbo of approx.100k miles. The not unusual symptoms of erratic idle persistently has been spoiling an otherwise fine car. Consulting previous posts on the forum I checked/replaced the hoses, plugs, dist cap, coolant temp sensor and throttle body switch. This resulted in a much smoother car but the revs jumping between 800 and 1200rpm continued once the operating temp was reached. Finally the car was passed to a general mechanic who suggested the following.
1. Remove the idle control valve
2. Plug one of the inlet openings
3. Fill with WD40, leave over night.
4. Refit
This weekend the car behaved impeccably surviving all the M25 J11-15 AND M40 could throw at it.
Hope this helps someone.

Common problem this, Crb cleaner or Brake cleaner is just as effective.

Works on all idle bypass/control valves whatever model.

My freind is having big touble with her 480 Auto when cold as it won't idle. Maybe the choke is not working?
Where are the Engine temp sensors and control valve you speak of and what do they look like?
Cheers Harvey

I've solved it! The plug under the throttle body which connects to the throttle position switch was the problem. It looked clean and corosion free but I cleaned it with WD and the problem has gone and it starts fine again now. You need to prise out the spring clip around the plug before it will undo.