Hi all. This isn't the typical high idle, 1700rpm in neutral situation which most people seem to get and is usually caused by the OVP or idle control valve.

The car is idling at about 1100rpm in neutral and 750 or so in gear. From all that I have read here after searching this is likely to be either the idle control valve or the idle control unit.

What can I do to isolate this further? Both parts are reasonably expensive so I don't want to just through parts at it without trying to be a little surer that it's one or the other or both.

Cheers
Matt.